diff --git a/services/web/app/src/Features/Authentication/AuthenticationController.mjs b/services/web/app/src/Features/Authentication/AuthenticationController.mjs
index f698c2fd3e..62efb907b3 100644
--- a/services/web/app/src/Features/Authentication/AuthenticationController.mjs
+++ b/services/web/app/src/Features/Authentication/AuthenticationController.mjs
@@ -24,7 +24,7 @@ import AdminAuthorizationHelper from '../Helpers/AdminAuthorizationHelper.mjs'
 import Modules from '../../infrastructure/Modules.js'
 import { expressify, promisify } from '@overleaf/promise-utils'
 import { handleAuthenticateErrors } from './AuthenticationErrors.js'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 
 const { hasAdminAccess } = AdminAuthorizationHelper
 
diff --git a/services/web/app/src/Features/Authentication/AuthenticationManager.mjs b/services/web/app/src/Features/Authentication/AuthenticationManager.mjs
index 0d45c4eaa8..c4455b7f51 100644
--- a/services/web/app/src/Features/Authentication/AuthenticationManager.mjs
+++ b/services/web/app/src/Features/Authentication/AuthenticationManager.mjs
@@ -1,8 +1,8 @@
 import Settings from '@overleaf/settings'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import { db, ObjectId } from '../../infrastructure/mongodb.js'
 import bcrypt from 'bcrypt'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 
 import {
   InvalidEmailError,
@@ -16,7 +16,7 @@ import { callbackify, callbackifyMultiResult } from '@overleaf/promise-utils'
 import HaveIBeenPwned from './HaveIBeenPwned.mjs'
 import UserAuditLogHandler from '../User/UserAuditLogHandler.mjs'
 import logger from '@overleaf/logger'
-import DiffHelper from '../Helpers/DiffHelper.mjs'
+import DiffHelper from '../Helpers/DiffHelper.js'
 import Metrics from '@overleaf/metrics'
 
 const BCRYPT_ROUNDS = Settings.security.bcryptRounds || 12
diff --git a/services/web/app/src/Features/Authorization/AuthorizationManager.mjs b/services/web/app/src/Features/Authorization/AuthorizationManager.mjs
index 7a9be587b9..55ce69e738 100644
--- a/services/web/app/src/Features/Authorization/AuthorizationManager.mjs
+++ b/services/web/app/src/Features/Authorization/AuthorizationManager.mjs
@@ -4,7 +4,7 @@ import Features from '../../infrastructure/Features.js'
 import CollaboratorsGetter from '../Collaborators/CollaboratorsGetter.mjs'
 import CollaboratorsHandler from '../Collaborators/CollaboratorsHandler.mjs'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import PrivilegeLevels from './PrivilegeLevels.js'
 import TokenAccessHandler from '../TokenAccess/TokenAccessHandler.mjs'
 import PublicAccessLevels from './PublicAccessLevels.mjs'
diff --git a/services/web/app/src/Features/Captcha/CaptchaMiddleware.mjs b/services/web/app/src/Features/Captcha/CaptchaMiddleware.mjs
index 45e0902617..42ae80d8cf 100644
--- a/services/web/app/src/Features/Captcha/CaptchaMiddleware.mjs
+++ b/services/web/app/src/Features/Captcha/CaptchaMiddleware.mjs
@@ -6,7 +6,7 @@ import OError from '@overleaf/o-error'
 import DeviceHistory from './DeviceHistory.mjs'
 import AuthenticationController from '../Authentication/AuthenticationController.mjs'
 import { expressify } from '@overleaf/promise-utils'
-import EmailsHelper from '../Helpers/EmailHelper.mjs'
+import EmailsHelper from '../Helpers/EmailHelper.js'
 
 function respondInvalidCaptcha(req, res) {
   res.status(400).json({
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsEmailHandler.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsEmailHandler.mjs
index aa84824e76..39b1bf12df 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsEmailHandler.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsEmailHandler.mjs
@@ -1,5 +1,5 @@
 import { callbackify } from 'node:util'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import EmailHandler from '../Email/EmailHandler.mjs'
 import Settings from '@overleaf/settings'
 
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsGetter.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsGetter.mjs
index b75a06f955..54d2112740 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsGetter.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsGetter.mjs
@@ -4,7 +4,7 @@ import { callbackify } from 'node:util'
 import pLimit from 'p-limit'
 import mongodb from 'mongodb-legacy'
 import OError from '@overleaf/o-error'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import UserGetter from '../User/UserGetter.mjs'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import PublicAccessLevels from '../Authorization/PublicAccessLevels.mjs'
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsHandler.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsHandler.mjs
index ab7f366315..1eee8a6936 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsHandler.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsHandler.mjs
@@ -1,6 +1,6 @@
 import { callbackify } from 'node:util'
 import OError from '@overleaf/o-error'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import logger from '@overleaf/logger'
 import ContactManager from '../Contacts/ContactManager.mjs'
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsInviteController.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsInviteController.mjs
index 75d280701e..33bdefd212 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsInviteController.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsInviteController.mjs
@@ -6,7 +6,7 @@ import CollaboratorsInviteHandler from './CollaboratorsInviteHandler.mjs'
 import CollaboratorsInviteGetter from './CollaboratorsInviteGetter.mjs'
 import logger from '@overleaf/logger'
 import Settings from '@overleaf/settings'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import EditorRealTimeController from '../Editor/EditorRealTimeController.mjs'
 import AnalyticsManager from '../Analytics/AnalyticsManager.mjs'
 import SessionManager from '../Authentication/SessionManager.mjs'
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsInviteGetter.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsInviteGetter.mjs
index 8ce4651e49..766f1f4708 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsInviteGetter.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsInviteGetter.mjs
@@ -1,5 +1,5 @@
 import logger from '@overleaf/logger'
-import { ProjectInvite } from '../../models/ProjectInvite.mjs'
+import { ProjectInvite } from '../../models/ProjectInvite.js'
 import PrivilegeLevels from '../Authorization/PrivilegeLevels.js'
 import CollaboratorsInviteHelper from './CollaboratorsInviteHelper.mjs'
 
diff --git a/services/web/app/src/Features/Collaborators/CollaboratorsInviteHandler.mjs b/services/web/app/src/Features/Collaborators/CollaboratorsInviteHandler.mjs
index 4c956dc102..58c99eeba5 100644
--- a/services/web/app/src/Features/Collaborators/CollaboratorsInviteHandler.mjs
+++ b/services/web/app/src/Features/Collaborators/CollaboratorsInviteHandler.mjs
@@ -1,5 +1,5 @@
 import { callbackify } from 'node:util'
-import { ProjectInvite } from '../../models/ProjectInvite.mjs'
+import { ProjectInvite } from '../../models/ProjectInvite.js'
 import logger from '@overleaf/logger'
 import CollaboratorsEmailHandler from './CollaboratorsEmailHandler.mjs'
 import CollaboratorsHandler from './CollaboratorsHandler.mjs'
diff --git a/services/web/app/src/Features/Collaborators/OwnershipTransferHandler.mjs b/services/web/app/src/Features/Collaborators/OwnershipTransferHandler.mjs
index 093f6893c8..79ed8b0435 100644
--- a/services/web/app/src/Features/Collaborators/OwnershipTransferHandler.mjs
+++ b/services/web/app/src/Features/Collaborators/OwnershipTransferHandler.mjs
@@ -1,5 +1,5 @@
 import logger from '@overleaf/logger'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import UserGetter from '../User/UserGetter.mjs'
 import CollaboratorsHandler from './CollaboratorsHandler.mjs'
diff --git a/services/web/app/src/Features/Cooldown/CooldownManager.mjs b/services/web/app/src/Features/Cooldown/CooldownManager.js
similarity index 83%
rename from services/web/app/src/Features/Cooldown/CooldownManager.mjs
rename to services/web/app/src/Features/Cooldown/CooldownManager.js
index 5f190d1a08..8c6b708c07 100644
--- a/services/web/app/src/Features/Cooldown/CooldownManager.mjs
+++ b/services/web/app/src/Features/Cooldown/CooldownManager.js
@@ -1,7 +1,7 @@
-import RedisWrapper from '../../infrastructure/RedisWrapper.js'
-import logger from '@overleaf/logger'
-import { promisify } from '@overleaf/promise-utils'
+const RedisWrapper = require('../../infrastructure/RedisWrapper')
 const rclient = RedisWrapper.client('cooldown')
+const logger = require('@overleaf/logger')
+const { promisify } = require('@overleaf/promise-utils')
 
 const COOLDOWN_IN_SECONDS = 60 * 10
 
@@ -45,4 +45,4 @@ CooldownManager.promises = {
   isProjectOnCooldown: promisify(CooldownManager.isProjectOnCooldown),
 }
 
-export default CooldownManager
+module.exports = CooldownManager
diff --git a/services/web/app/src/Features/Cooldown/CooldownMiddleware.mjs b/services/web/app/src/Features/Cooldown/CooldownMiddleware.mjs
index d2d1cb01e3..46a84eb571 100644
--- a/services/web/app/src/Features/Cooldown/CooldownMiddleware.mjs
+++ b/services/web/app/src/Features/Cooldown/CooldownMiddleware.mjs
@@ -10,7 +10,7 @@
  * DS207: Consider shorter variations of null checks
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
-import CooldownManager from './CooldownManager.mjs'
+import CooldownManager from './CooldownManager.js'
 import logger from '@overleaf/logger'
 
 let CooldownMiddleware
diff --git a/services/web/app/src/Features/FileStore/FileStoreHandler.mjs b/services/web/app/src/Features/FileStore/FileStoreHandler.mjs
index 6abc6602b9..982616f44b 100644
--- a/services/web/app/src/Features/FileStore/FileStoreHandler.mjs
+++ b/services/web/app/src/Features/FileStore/FileStoreHandler.mjs
@@ -4,7 +4,7 @@ import Async from 'async'
 import FileHashManager from './FileHashManager.mjs'
 import HistoryManager from '../History/HistoryManager.mjs'
 import ProjectDetailsHandler from '../Project/ProjectDetailsHandler.mjs'
-import { File } from '../../models/File.mjs'
+import { File } from '../../models/File.js'
 import OError from '@overleaf/o-error'
 import { promisifyAll } from '@overleaf/promise-utils'
 import Modules from '../../infrastructure/Modules.js'
diff --git a/services/web/app/src/Features/GlobalMetrics/GlobalMetricsManager.mjs b/services/web/app/src/Features/GlobalMetrics/GlobalMetricsManager.mjs
index 5be629f490..d8991614d7 100644
--- a/services/web/app/src/Features/GlobalMetrics/GlobalMetricsManager.mjs
+++ b/services/web/app/src/Features/GlobalMetrics/GlobalMetricsManager.mjs
@@ -1,4 +1,4 @@
-import { GlobalMetric } from '../../models/GlobalMetric.mjs'
+import { GlobalMetric } from '../../models/GlobalMetric.js'
 /**
  * A Generic collection used to track metrics shared across the entirety of the application
  * examples:
diff --git a/services/web/app/src/Features/Helpers/AuthorizationHelper.mjs b/services/web/app/src/Features/Helpers/AuthorizationHelper.mjs
index 9d16102113..9bac0c0769 100644
--- a/services/web/app/src/Features/Helpers/AuthorizationHelper.mjs
+++ b/services/web/app/src/Features/Helpers/AuthorizationHelper.mjs
@@ -1,4 +1,4 @@
-import { UserSchema } from '../../models/User.mjs'
+import { UserSchema } from '../../models/User.js'
 
 export default {
   hasAnyStaffAccess,
diff --git a/services/web/app/src/Features/Helpers/DiffHelper.mjs b/services/web/app/src/Features/Helpers/DiffHelper.js
similarity index 95%
rename from services/web/app/src/Features/Helpers/DiffHelper.mjs
rename to services/web/app/src/Features/Helpers/DiffHelper.js
index b8b2b3005a..c2d1d73fd3 100644
--- a/services/web/app/src/Features/Helpers/DiffHelper.mjs
+++ b/services/web/app/src/Features/Helpers/DiffHelper.js
@@ -17,7 +17,7 @@ function _calculateRatio(matches, length) {
  * corresponding (approximatey) to the overlap between the strings.
  * Identical strings produce 1.0, completely different strings produce 0.0
  * */
-export function stringSimilarity(a, b) {
+function stringSimilarity(a, b) {
   if (
     typeof a !== 'string' ||
     typeof b !== 'string' ||
@@ -50,6 +50,6 @@ export function stringSimilarity(a, b) {
   return _calculateRatio(matches, a.length + b.length)
 }
 
-export default {
+module.exports = {
   stringSimilarity,
 }
diff --git a/services/web/app/src/Features/Helpers/EmailHelper.mjs b/services/web/app/src/Features/Helpers/EmailHelper.js
similarity index 90%
rename from services/web/app/src/Features/Helpers/EmailHelper.mjs
rename to services/web/app/src/Features/Helpers/EmailHelper.js
index 34e96b91d9..80b96dfea0 100644
--- a/services/web/app/src/Features/Helpers/EmailHelper.mjs
+++ b/services/web/app/src/Features/Helpers/EmailHelper.js
@@ -1,6 +1,4 @@
-import emailAddresses from 'email-addresses'
-
-const { parseOneAddress } = emailAddresses
+const { parseOneAddress } = require('email-addresses')
 
 // available for frontend in https://github.com/overleaf/internal/blob/19d432c70b173752ee7c6d8978dd6be16b042921/services/web/frontend/js/shared/utils/email.tsx#L4
 const EMAIL_REGEXP =
@@ -38,7 +36,7 @@ function parseEmail(email, parseRfcAddress = false) {
   return matched[0]
 }
 
-export default {
+module.exports = {
   getDomain,
   parseEmail,
 }
diff --git a/services/web/app/src/Features/InactiveData/InactiveProjectManager.mjs b/services/web/app/src/Features/InactiveData/InactiveProjectManager.mjs
index be91231fd3..6ec4c0f6b4 100644
--- a/services/web/app/src/Features/InactiveData/InactiveProjectManager.mjs
+++ b/services/web/app/src/Features/InactiveData/InactiveProjectManager.mjs
@@ -4,7 +4,7 @@ import DocstoreManager from '../Docstore/DocstoreManager.mjs'
 import DocumentUpdaterHandler from '../DocumentUpdater/DocumentUpdaterHandler.mjs'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import ProjectUpdateHandler from '../Project/ProjectUpdateHandler.mjs'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import Modules from '../../infrastructure/Modules.js'
 import { READ_PREFERENCE_SECONDARY } from '../../infrastructure/mongodb.js'
 import { callbackifyAll } from '@overleaf/promise-utils'
diff --git a/services/web/app/src/Features/Institutions/InstitutionsManager.mjs b/services/web/app/src/Features/Institutions/InstitutionsManager.mjs
index 989aa6596b..9c6c9d2f6e 100644
--- a/services/web/app/src/Features/Institutions/InstitutionsManager.mjs
+++ b/services/web/app/src/Features/Institutions/InstitutionsManager.mjs
@@ -10,8 +10,8 @@ import UserGetter from '../User/UserGetter.mjs'
 import NotificationsBuilder from '../Notifications/NotificationsBuilder.mjs'
 import NotificationsHandler from '../Notifications/NotificationsHandler.mjs'
 import SubscriptionLocator from '../Subscription/SubscriptionLocator.mjs'
-import { Institution } from '../../models/Institution.mjs'
-import { Subscription } from '../../models/Subscription.mjs'
+import { Institution } from '../../models/Institution.js'
+import { Subscription } from '../../models/Subscription.js'
 import OError from '@overleaf/o-error'
 
 const { ObjectId } = mongodb
diff --git a/services/web/app/src/Features/LinkedFiles/LinkedFilesHandler.mjs b/services/web/app/src/Features/LinkedFiles/LinkedFilesHandler.mjs
index 4bbc9069b8..2cd8272ece 100644
--- a/services/web/app/src/Features/LinkedFiles/LinkedFilesHandler.mjs
+++ b/services/web/app/src/Features/LinkedFiles/LinkedFilesHandler.mjs
@@ -1,7 +1,7 @@
 import FileWriter from '../../infrastructure/FileWriter.js'
 import EditorController from '../Editor/EditorController.mjs'
 import ProjectLocator from '../Project/ProjectLocator.mjs'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import LinkedFilesErrors from './LinkedFilesErrors.mjs'
 import { callbackifyAll } from '@overleaf/promise-utils'
diff --git a/services/web/app/src/Features/OnboardingDataCollection/OnboardingDataCollectionManager.mjs b/services/web/app/src/Features/OnboardingDataCollection/OnboardingDataCollectionManager.mjs
index 99bb0a3d7a..8359add440 100644
--- a/services/web/app/src/Features/OnboardingDataCollection/OnboardingDataCollectionManager.mjs
+++ b/services/web/app/src/Features/OnboardingDataCollection/OnboardingDataCollectionManager.mjs
@@ -1,4 +1,4 @@
-import OnboardingDataCollectionModel from '../../models/OnboardingDataCollection.mjs'
+import OnboardingDataCollectionModel from '../../models/OnboardingDataCollection.js'
 import OError from '@overleaf/o-error'
 
 const { OnboardingDataCollection, OnboardingDataCollectionSchema } =
diff --git a/services/web/app/src/Features/PasswordReset/PasswordResetController.mjs b/services/web/app/src/Features/PasswordReset/PasswordResetController.mjs
index a945c93ffd..d9221f23b5 100644
--- a/services/web/app/src/Features/PasswordReset/PasswordResetController.mjs
+++ b/services/web/app/src/Features/PasswordReset/PasswordResetController.mjs
@@ -6,7 +6,7 @@ import UserGetter from '../User/UserGetter.mjs'
 import UserUpdater from '../User/UserUpdater.mjs'
 import UserSessionsManager from '../User/UserSessionsManager.mjs'
 import OError from '@overleaf/o-error'
-import EmailsHelper from '../Helpers/EmailHelper.mjs'
+import EmailsHelper from '../Helpers/EmailHelper.js'
 import { expressify } from '@overleaf/promise-utils'
 import { z, validateReq } from '../../infrastructure/Validation.js'
 
diff --git a/services/web/app/src/Features/PasswordReset/PasswordResetHandler.mjs b/services/web/app/src/Features/PasswordReset/PasswordResetHandler.mjs
index 33d785e80f..5ff08f36c2 100644
--- a/services/web/app/src/Features/PasswordReset/PasswordResetHandler.mjs
+++ b/services/web/app/src/Features/PasswordReset/PasswordResetHandler.mjs
@@ -1,7 +1,7 @@
 import settings from '@overleaf/settings'
 import UserAuditLogHandler from '../User/UserAuditLogHandler.mjs'
 import UserGetter from '../User/UserGetter.mjs'
-import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.mjs'
+import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.js'
 import EmailHandler from '../Email/EmailHandler.mjs'
 import AuthenticationManager from '../Authentication/AuthenticationManager.mjs'
 import { callbackify, promisify } from 'node:util'
diff --git a/services/web/app/src/Features/Project/IterablePath.mjs b/services/web/app/src/Features/Project/IterablePath.js
similarity index 74%
rename from services/web/app/src/Features/Project/IterablePath.mjs
rename to services/web/app/src/Features/Project/IterablePath.js
index 1c6ad90eb5..52cf068c42 100644
--- a/services/web/app/src/Features/Project/IterablePath.mjs
+++ b/services/web/app/src/Features/Project/IterablePath.js
@@ -3,9 +3,13 @@
  * `folder.folders` or `folder.fileRefs` are missing it returns an
  * empty array.
  */
-export function iterablePaths(folder, field) {
+function iterablePaths(folder, field) {
   if (!folder) {
     return []
   }
   return folder[field] || []
 }
+
+module.exports = {
+  iterablePaths,
+}
diff --git a/services/web/app/src/Features/Project/ProjectAuditLogHandler.mjs b/services/web/app/src/Features/Project/ProjectAuditLogHandler.mjs
index 753987c0b7..8a594a7801 100644
--- a/services/web/app/src/Features/Project/ProjectAuditLogHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectAuditLogHandler.mjs
@@ -1,5 +1,5 @@
 import logger from '@overleaf/logger'
-import { ProjectAuditLogEntry } from '../../models/ProjectAuditLogEntry.mjs'
+import { ProjectAuditLogEntry } from '../../models/ProjectAuditLogEntry.js'
 import { callbackify } from '@overleaf/promise-utils'
 import SubscriptionLocator from '../Subscription/SubscriptionLocator.mjs'
 
diff --git a/services/web/app/src/Features/Project/ProjectCollabratecDetailsHandler.mjs b/services/web/app/src/Features/Project/ProjectCollabratecDetailsHandler.mjs
index d9f66b66fc..55d19a4bd6 100644
--- a/services/web/app/src/Features/Project/ProjectCollabratecDetailsHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectCollabratecDetailsHandler.mjs
@@ -1,6 +1,6 @@
 import mongodb from 'mongodb-legacy'
 
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import { callbackifyAll } from '@overleaf/promise-utils'
 
 const { ObjectId } = mongodb
diff --git a/services/web/app/src/Features/Project/ProjectController.mjs b/services/web/app/src/Features/Project/ProjectController.mjs
index 6186f9af44..5d89b2c850 100644
--- a/services/web/app/src/Features/Project/ProjectController.mjs
+++ b/services/web/app/src/Features/Project/ProjectController.mjs
@@ -12,9 +12,9 @@ import ProjectCreationHandler from './ProjectCreationHandler.mjs'
 import EditorController from '../Editor/EditorController.mjs'
 import ProjectHelper from './ProjectHelper.mjs'
 import metrics from '@overleaf/metrics'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import SubscriptionLocator from '../Subscription/SubscriptionLocator.mjs'
-import SubscriptionHelper from '../Subscription/SubscriptionHelper.mjs'
+import { isPaidSubscription } from '../Subscription/SubscriptionHelper.js'
 import LimitationsManager from '../Subscription/LimitationsManager.mjs'
 import Settings from '@overleaf/settings'
 import AuthorizationManager from '../Authorization/AuthorizationManager.mjs'
@@ -52,7 +52,6 @@ import SubscriptionController from '../Subscription/SubscriptionController.mjs'
 import { formatCurrency } from '../../util/currency.js'
 import UserSettingsHelper from './UserSettingsHelper.mjs'
 
-const { isPaidSubscription } = SubscriptionHelper
 const { hasAdminAccess } = AdminAuthorizationHelper
 const { ObjectId } = mongodb
 /**
diff --git a/services/web/app/src/Features/Project/ProjectCreationHandler.mjs b/services/web/app/src/Features/Project/ProjectCreationHandler.mjs
index 03ad4437a2..ef614f7f05 100644
--- a/services/web/app/src/Features/Project/ProjectCreationHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectCreationHandler.mjs
@@ -3,12 +3,12 @@ import metrics from '@overleaf/metrics'
 import Settings from '@overleaf/settings'
 import mongodb from 'mongodb-legacy'
 import Features from '../../infrastructure/Features.js'
-import { Project } from '../../models/Project.mjs'
-import { Folder } from '../../models/Folder.mjs'
+import { Project } from '../../models/Project.js'
+import { Folder } from '../../models/Folder.js'
 import ProjectEntityUpdateHandler from './ProjectEntityUpdateHandler.mjs'
 import ProjectDetailsHandler from './ProjectDetailsHandler.mjs'
 import HistoryManager from '../History/HistoryManager.mjs'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import fs from 'node:fs'
 import path from 'node:path'
 import { callbackify } from 'node:util'
diff --git a/services/web/app/src/Features/Project/ProjectDeleter.mjs b/services/web/app/src/Features/Project/ProjectDeleter.mjs
index eda7671270..276e3765cb 100644
--- a/services/web/app/src/Features/Project/ProjectDeleter.mjs
+++ b/services/web/app/src/Features/Project/ProjectDeleter.mjs
@@ -6,9 +6,9 @@ import {
 } from '../../infrastructure/mongodb.js'
 import Modules from '../../infrastructure/Modules.js'
 import { callbackify } from 'node:util'
-import { Project } from '../../models/Project.mjs'
-import { DeletedProject } from '../../models/DeletedProject.mjs'
-import { ProjectAuditLogEntry } from '../../models/ProjectAuditLogEntry.mjs'
+import { Project } from '../../models/Project.js'
+import { DeletedProject } from '../../models/DeletedProject.js'
+import { ProjectAuditLogEntry } from '../../models/ProjectAuditLogEntry.js'
 import Errors from '../Errors/Errors.js'
 import logger from '@overleaf/logger'
 import Settings from '@overleaf/settings'
diff --git a/services/web/app/src/Features/Project/ProjectDetailsHandler.mjs b/services/web/app/src/Features/Project/ProjectDetailsHandler.mjs
index a2116ecdf3..758429dae6 100644
--- a/services/web/app/src/Features/Project/ProjectDetailsHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectDetailsHandler.mjs
@@ -1,7 +1,7 @@
 import _ from 'lodash'
 import ProjectGetter from './ProjectGetter.mjs'
 import UserGetter from '../User/UserGetter.mjs'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import logger from '@overleaf/logger'
 import TpdsUpdateSender from '../ThirdPartyDataStore/TpdsUpdateSender.mjs'
 import PublicAccessLevels from '../Authorization/PublicAccessLevels.mjs'
diff --git a/services/web/app/src/Features/Project/ProjectDuplicator.mjs b/services/web/app/src/Features/Project/ProjectDuplicator.mjs
index d125578651..1f2ec0f773 100644
--- a/services/web/app/src/Features/Project/ProjectDuplicator.mjs
+++ b/services/web/app/src/Features/Project/ProjectDuplicator.mjs
@@ -3,8 +3,8 @@ import Path from 'node:path'
 import logger from '@overleaf/logger'
 import OError from '@overleaf/o-error'
 import { promiseMapWithLimit } from '@overleaf/promise-utils'
-import { Doc } from '../../models/Doc.mjs'
-import { File } from '../../models/File.mjs'
+import { Doc } from '../../models/Doc.js'
+import { File } from '../../models/File.js'
 import DocstoreManager from '../Docstore/DocstoreManager.mjs'
 import DocumentUpdaterHandler from '../DocumentUpdater/DocumentUpdaterHandler.mjs'
 import HistoryManager from '../History/HistoryManager.mjs'
diff --git a/services/web/app/src/Features/Project/ProjectEntityHandler.mjs b/services/web/app/src/Features/Project/ProjectEntityHandler.mjs
index acc4e26438..8a2e18c0d8 100644
--- a/services/web/app/src/Features/Project/ProjectEntityHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectEntityHandler.mjs
@@ -4,7 +4,7 @@ import Errors from '../Errors/Errors.js'
 import ProjectGetter from './ProjectGetter.mjs'
 import { callbackifyAll } from '@overleaf/promise-utils'
 import OError from '@overleaf/o-error'
-import { iterablePaths } from './IterablePath.mjs'
+import { iterablePaths } from './IterablePath.js'
 
 async function getAllDocs(projectId) {
   // We get the path and name info from the project, and the lines and
diff --git a/services/web/app/src/Features/Project/ProjectEntityMongoUpdateHandler.mjs b/services/web/app/src/Features/Project/ProjectEntityMongoUpdateHandler.mjs
index 59e0d72619..2843621d52 100644
--- a/services/web/app/src/Features/Project/ProjectEntityMongoUpdateHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectEntityMongoUpdateHandler.mjs
@@ -5,17 +5,17 @@ import path from 'node:path'
 import mongodb from 'mongodb-legacy'
 import Settings from '@overleaf/settings'
 import OError from '@overleaf/o-error'
-import CooldownManager from '../Cooldown/CooldownManager.mjs'
+import CooldownManager from '../Cooldown/CooldownManager.js'
 import Errors from '../Errors/Errors.js'
-import { Folder } from '../../models/Folder.mjs'
+import { Folder } from '../../models/Folder.js'
 import LockManager from '../../infrastructure/LockManager.js'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectEntityHandler from './ProjectEntityHandler.mjs'
 import ProjectGetter from './ProjectGetter.mjs'
 import ProjectLocator from './ProjectLocator.mjs'
 import FolderStructureBuilder from './FolderStructureBuilder.mjs'
 import SafePath from './SafePath.mjs'
-import { iterablePaths } from './IterablePath.mjs'
+import { iterablePaths } from './IterablePath.js'
 
 const { ObjectId } = mongodb
 
diff --git a/services/web/app/src/Features/Project/ProjectEntityUpdateHandler.mjs b/services/web/app/src/Features/Project/ProjectEntityUpdateHandler.mjs
index 34d76d893c..0a482cea73 100644
--- a/services/web/app/src/Features/Project/ProjectEntityUpdateHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectEntityUpdateHandler.mjs
@@ -4,13 +4,13 @@ import logger from '@overleaf/logger'
 import Settings from '@overleaf/settings'
 import Path from 'node:path'
 import fs from 'node:fs'
-import { Doc } from '../../models/Doc.mjs'
+import { Doc } from '../../models/Doc.js'
 import DocstoreManager from '../Docstore/DocstoreManager.mjs'
 import DocumentUpdaterHandler from '../../Features/DocumentUpdater/DocumentUpdaterHandler.mjs'
 import Errors from '../Errors/Errors.js'
 import FileStoreHandler from '../FileStore/FileStoreHandler.mjs'
 import LockManager from '../../infrastructure/LockManager.js'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectEntityHandler from './ProjectEntityHandler.mjs'
 import ProjectGetter from './ProjectGetter.mjs'
 import ProjectLocator from './ProjectLocator.mjs'
@@ -22,7 +22,7 @@ import TpdsUpdateSender from '../ThirdPartyDataStore/TpdsUpdateSender.mjs'
 import FileWriter from '../../infrastructure/FileWriter.js'
 import EditorRealTimeController from '../Editor/EditorRealTimeController.mjs'
 import { callbackifyMultiResult, callbackify } from '@overleaf/promise-utils'
-import { iterablePaths } from './IterablePath.mjs'
+import { iterablePaths } from './IterablePath.js'
 
 const LOCK_NAMESPACE = 'sequentialProjectStructureUpdateLock'
 const VALID_ROOT_DOC_EXTENSIONS = Settings.validRootDocExtensions
diff --git a/services/web/app/src/Features/Project/ProjectGetter.mjs b/services/web/app/src/Features/Project/ProjectGetter.mjs
index 2aafb73892..0903a0504c 100644
--- a/services/web/app/src/Features/Project/ProjectGetter.mjs
+++ b/services/web/app/src/Features/Project/ProjectGetter.mjs
@@ -1,9 +1,9 @@
 import { db } from '../../infrastructure/mongodb.js'
 import { normalizeQuery } from '../Helpers/Mongo.js'
 import OError from '@overleaf/o-error'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import LockManager from '../../infrastructure/LockManager.js'
-import { DeletedProject } from '../../models/DeletedProject.mjs'
+import { DeletedProject } from '../../models/DeletedProject.js'
 import { callbackifyAll } from '@overleaf/promise-utils'
 import ProjectEntityMongoUpdateHandler from './ProjectEntityMongoUpdateHandler.mjs'
 import CollaboratorsGetter from '../Collaborators/CollaboratorsGetter.mjs'
diff --git a/services/web/app/src/Features/Project/ProjectHistoryHandler.mjs b/services/web/app/src/Features/Project/ProjectHistoryHandler.mjs
index adbae9dfab..b08533522e 100644
--- a/services/web/app/src/Features/Project/ProjectHistoryHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectHistoryHandler.mjs
@@ -1,4 +1,4 @@
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectDetailsHandler from './ProjectDetailsHandler.mjs'
 import HistoryManager from '../History/HistoryManager.mjs'
 import ProjectEntityUpdateHandler from './ProjectEntityUpdateHandler.mjs'
diff --git a/services/web/app/src/Features/Project/ProjectListController.mjs b/services/web/app/src/Features/Project/ProjectListController.mjs
index 0cfb78a099..2e5a5fc1e3 100644
--- a/services/web/app/src/Features/Project/ProjectListController.mjs
+++ b/services/web/app/src/Features/Project/ProjectListController.mjs
@@ -19,7 +19,7 @@ import SubscriptionViewModelBuilder from '../Subscription/SubscriptionViewModelB
 import NotificationsHandler from '../Notifications/NotificationsHandler.mjs'
 import Modules from '../../infrastructure/Modules.js'
 import { OError, V1ConnectionError } from '../Errors/Errors.js'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import UserPrimaryEmailCheckHandler from '../User/UserPrimaryEmailCheckHandler.mjs'
 import UserController from '../User/UserController.mjs'
 import NotificationsBuilder from '../Notifications/NotificationsBuilder.mjs'
@@ -27,10 +27,10 @@ import GeoIpLookup from '../../infrastructure/GeoIpLookup.mjs'
 import SplitTestHandler from '../SplitTests/SplitTestHandler.mjs'
 import SplitTestSessionHandler from '../SplitTests/SplitTestSessionHandler.mjs'
 import TutorialHandler from '../Tutorial/TutorialHandler.mjs'
-import SubscriptionHelper from '../Subscription/SubscriptionHelper.mjs'
+import SubscriptionHelper from '../Subscription/SubscriptionHelper.js'
 import PermissionsManager from '../Authorization/PermissionsManager.mjs'
 import AnalyticsManager from '../Analytics/AnalyticsManager.mjs'
-import { OnboardingDataCollection } from '../../models/OnboardingDataCollection.mjs'
+import { OnboardingDataCollection } from '../../models/OnboardingDataCollection.js'
 import UserSettingsHelper from './UserSettingsHelper.mjs'
 
 /**
diff --git a/services/web/app/src/Features/Project/ProjectLocator.mjs b/services/web/app/src/Features/Project/ProjectLocator.mjs
index abc80b9dcb..3a3d8ba962 100644
--- a/services/web/app/src/Features/Project/ProjectLocator.mjs
+++ b/services/web/app/src/Features/Project/ProjectLocator.mjs
@@ -5,7 +5,7 @@ import async from 'async'
 import ProjectGetter from './ProjectGetter.mjs'
 import Errors from '../Errors/Errors.js'
 import { promisifyMultiResult } from '@overleaf/promise-utils'
-import { iterablePaths } from './IterablePath.mjs'
+import { iterablePaths } from './IterablePath.js'
 
 /**
  * @param project
diff --git a/services/web/app/src/Features/Project/ProjectOptionsHandler.mjs b/services/web/app/src/Features/Project/ProjectOptionsHandler.mjs
index d80e8c75c8..9d577fc35e 100644
--- a/services/web/app/src/Features/Project/ProjectOptionsHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectOptionsHandler.mjs
@@ -1,4 +1,4 @@
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import settings from '@overleaf/settings'
 import { callbackify } from 'node:util'
 import { db, ObjectId } from '../../infrastructure/mongodb.js'
diff --git a/services/web/app/src/Features/Project/ProjectUpdateHandler.mjs b/services/web/app/src/Features/Project/ProjectUpdateHandler.mjs
index f4b366acc0..2352ef1ad1 100644
--- a/services/web/app/src/Features/Project/ProjectUpdateHandler.mjs
+++ b/services/web/app/src/Features/Project/ProjectUpdateHandler.mjs
@@ -1,4 +1,4 @@
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import { callbackify } from 'node:util'
 
 const ProjectUpdateHandler = {
diff --git a/services/web/app/src/Features/Referal/ReferalAllocator.mjs b/services/web/app/src/Features/Referal/ReferalAllocator.mjs
index 5fb2c714b9..6e37a5c063 100644
--- a/services/web/app/src/Features/Referal/ReferalAllocator.mjs
+++ b/services/web/app/src/Features/Referal/ReferalAllocator.mjs
@@ -1,5 +1,5 @@
 import OError from '@overleaf/o-error'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import FeaturesUpdater from '../Subscription/FeaturesUpdater.mjs'
 import { callbackify } from '@overleaf/promise-utils'
 
diff --git a/services/web/app/src/Features/Referal/ReferalFeatures.mjs b/services/web/app/src/Features/Referal/ReferalFeatures.mjs
index dfb725927b..5ee8541786 100644
--- a/services/web/app/src/Features/Referal/ReferalFeatures.mjs
+++ b/services/web/app/src/Features/Referal/ReferalFeatures.mjs
@@ -1,6 +1,6 @@
 import _ from 'lodash'
 import { callbackify } from 'node:util'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import Settings from '@overleaf/settings'
 
 const ReferalFeatures = {
diff --git a/services/web/app/src/Features/Referal/ReferalHandler.mjs b/services/web/app/src/Features/Referal/ReferalHandler.mjs
index 3821fbb6ea..1d389bb860 100644
--- a/services/web/app/src/Features/Referal/ReferalHandler.mjs
+++ b/services/web/app/src/Features/Referal/ReferalHandler.mjs
@@ -1,5 +1,5 @@
 import { callbackify } from '@overleaf/promise-utils'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 
 async function getReferedUsers(userId) {
   const projection = { refered_users: 1, refered_user_count: 1 }
diff --git a/services/web/app/src/Features/SamlLog/SamlLogHandler.mjs b/services/web/app/src/Features/SamlLog/SamlLogHandler.mjs
index c55043291a..37845c6be2 100644
--- a/services/web/app/src/Features/SamlLog/SamlLogHandler.mjs
+++ b/services/web/app/src/Features/SamlLog/SamlLogHandler.mjs
@@ -1,4 +1,4 @@
-import { SamlLog } from '../../models/SamlLog.mjs'
+import { SamlLog } from '../../models/SamlLog.js'
 import SessionManager from '../Authentication/SessionManager.mjs'
 import logger from '@overleaf/logger'
 import loggerSerializers from '@overleaf/logger/serializers.js'
diff --git a/services/web/app/src/Features/Security/OneTimeTokenHandler.mjs b/services/web/app/src/Features/Security/OneTimeTokenHandler.js
similarity index 92%
rename from services/web/app/src/Features/Security/OneTimeTokenHandler.mjs
rename to services/web/app/src/Features/Security/OneTimeTokenHandler.js
index 2bfb7844e3..2b38f15635 100644
--- a/services/web/app/src/Features/Security/OneTimeTokenHandler.mjs
+++ b/services/web/app/src/Features/Security/OneTimeTokenHandler.js
@@ -1,7 +1,7 @@
-import crypto from 'node:crypto'
-import { db } from '../../infrastructure/mongodb.js'
-import Errors from '../Errors/Errors.js'
-import { callbackify } from 'node:util'
+const crypto = require('crypto')
+const { db } = require('../../infrastructure/mongodb')
+const Errors = require('../Errors/Errors')
+const { callbackify } = require('util')
 
 const ONE_HOUR_IN_S = 60 * 60
 
@@ -119,4 +119,4 @@ const OneTimeTokenHandler = {
   },
 }
 
-export default OneTimeTokenHandler
+module.exports = OneTimeTokenHandler
diff --git a/services/web/app/src/Features/SplitTests/SplitTestHandler.mjs b/services/web/app/src/Features/SplitTests/SplitTestHandler.mjs
index 36501f2be4..df82b8074b 100644
--- a/services/web/app/src/Features/SplitTests/SplitTestHandler.mjs
+++ b/services/web/app/src/Features/SplitTests/SplitTestHandler.mjs
@@ -6,7 +6,7 @@ import crypto from 'node:crypto'
 import _ from 'lodash'
 import { callbackify } from 'node:util'
 import SplitTestCache from './SplitTestCache.mjs'
-import { SplitTest } from '../../models/SplitTest.mjs'
+import { SplitTest } from '../../models/SplitTest.js'
 import UserAnalyticsIdCache from '../Analytics/UserAnalyticsIdCache.mjs'
 import Features from '../../infrastructure/Features.js'
 import SplitTestUtils from './SplitTestUtils.mjs'
diff --git a/services/web/app/src/Features/SplitTests/SplitTestManager.mjs b/services/web/app/src/Features/SplitTests/SplitTestManager.mjs
index 27b05dc6e1..587e75ef34 100644
--- a/services/web/app/src/Features/SplitTests/SplitTestManager.mjs
+++ b/services/web/app/src/Features/SplitTests/SplitTestManager.mjs
@@ -1,4 +1,4 @@
-import { SplitTest } from '../../models/SplitTest.mjs'
+import { SplitTest } from '../../models/SplitTest.js'
 import SplitTestUtils from './SplitTestUtils.mjs'
 import OError from '@overleaf/o-error'
 import _ from 'lodash'
diff --git a/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs b/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
index 9b318ba5d2..ee75dfb017 100644
--- a/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
+++ b/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
@@ -3,7 +3,7 @@ import { callbackify } from 'node:util'
 import { callbackifyMultiResult } from '@overleaf/promise-utils'
 import PlansLocator from './PlansLocator.mjs'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import UserFeaturesUpdater from './UserFeaturesUpdater.mjs'
 import FeaturesHelper from './FeaturesHelper.mjs'
 import Settings from '@overleaf/settings'
diff --git a/services/web/app/src/Features/Subscription/PaymentProviderEntities.mjs b/services/web/app/src/Features/Subscription/PaymentProviderEntities.mjs
index 0e5ba6aadf..089673c34d 100644
--- a/services/web/app/src/Features/Subscription/PaymentProviderEntities.mjs
+++ b/services/web/app/src/Features/Subscription/PaymentProviderEntities.mjs
@@ -20,7 +20,7 @@ import OError from '@overleaf/o-error'
 
 import { DuplicateAddOnError, AddOnNotPresentError } from './Errors.js'
 import PlansLocator from './PlansLocator.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import { AI_ADD_ON_CODE, isStandaloneAiAddOnPlanCode } from './AiHelper.js'
 export const MEMBERS_LIMIT_ADD_ON_CODE = 'additional-license'
 
diff --git a/services/web/app/src/Features/Subscription/SubscriptionController.mjs b/services/web/app/src/Features/Subscription/SubscriptionController.mjs
index 0dade58bce..ca21ca6f51 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionController.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionController.mjs
@@ -2,7 +2,7 @@
 
 import SessionManager from '../Authentication/SessionManager.mjs'
 import SubscriptionHandler from './SubscriptionHandler.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import SubscriptionViewModelBuilder from './SubscriptionViewModelBuilder.mjs'
 import LimitationsManager from './LimitationsManager.mjs'
 import RecurlyWrapper from './RecurlyWrapper.mjs'
@@ -28,7 +28,7 @@ import {
   subscriptionChangeIsAiAssistUpgrade,
 } from './AiHelper.js'
 import PlansLocator from './PlansLocator.mjs'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import UserGetter from '../User/UserGetter.mjs'
 import PermissionsManager from '../Authorization/PermissionsManager.mjs'
 import { sanitizeSessionUserForFrontEnd } from '../../infrastructure/FrontEndUser.mjs'
diff --git a/services/web/app/src/Features/Subscription/SubscriptionGroupController.mjs b/services/web/app/src/Features/Subscription/SubscriptionGroupController.mjs
index f9fe532391..c308be313f 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionGroupController.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionGroupController.mjs
@@ -8,7 +8,7 @@ import UserAuditLogHandler from '../User/UserAuditLogHandler.mjs'
 import { expressify } from '@overleaf/promise-utils'
 import Modules from '../../infrastructure/Modules.js'
 import UserGetter from '../User/UserGetter.mjs'
-import { Subscription } from '../../models/Subscription.mjs'
+import { Subscription } from '../../models/Subscription.js'
 import { z, validateReq } from '../../infrastructure/Validation.js'
 import { isProfessionalGroupPlan } from './PlansHelper.mjs'
 import {
diff --git a/services/web/app/src/Features/Subscription/SubscriptionGroupHandler.mjs b/services/web/app/src/Features/Subscription/SubscriptionGroupHandler.mjs
index 3a14f74cc0..3c6e485059 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionGroupHandler.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionGroupHandler.mjs
@@ -4,9 +4,9 @@ import OError from '@overleaf/o-error'
 import SubscriptionUpdater from './SubscriptionUpdater.mjs'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
 import SubscriptionController from './SubscriptionController.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
-import { Subscription } from '../../models/Subscription.mjs'
-import { User } from '../../models/User.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
+import { Subscription } from '../../models/Subscription.js'
+import { User } from '../../models/User.js'
 import PlansLocator from './PlansLocator.mjs'
 import TeamInvitesHandler from './TeamInvitesHandler.mjs'
 import GroupPlansData from './GroupPlansData.js'
@@ -19,7 +19,7 @@ import {
   HasPastDueInvoiceError,
   HasNoAdditionalLicenseWhenManuallyCollectedError,
 } from './Errors.js'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import { InvalidEmailError } from '../Errors/Errors.js'
 
 const MEMBERS_LIMIT_ADD_ON_CODE =
diff --git a/services/web/app/src/Features/Subscription/SubscriptionHandler.mjs b/services/web/app/src/Features/Subscription/SubscriptionHandler.mjs
index edd5456230..774705654e 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionHandler.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionHandler.mjs
@@ -3,9 +3,9 @@
 import RecurlyWrapper from './RecurlyWrapper.mjs'
 
 import RecurlyClient from './RecurlyClient.mjs'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import logger from '@overleaf/logger'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import SubscriptionUpdater from './SubscriptionUpdater.mjs'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
 import LimitationsManager from './LimitationsManager.mjs'
diff --git a/services/web/app/src/Features/Subscription/SubscriptionHelper.mjs b/services/web/app/src/Features/Subscription/SubscriptionHelper.js
similarity index 95%
rename from services/web/app/src/Features/Subscription/SubscriptionHelper.mjs
rename to services/web/app/src/Features/Subscription/SubscriptionHelper.js
index d97bc3bdd2..d65a7d3304 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionHelper.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionHelper.js
@@ -1,7 +1,7 @@
-import { formatCurrency } from '../../util/currency.js'
-import GroupPlansData from './GroupPlansData.js'
-import { isStandaloneAiAddOnPlanCode } from './AiHelper.js'
-import { Subscription } from '../../models/Subscription.mjs'
+const { formatCurrency } = require('../../util/currency')
+const GroupPlansData = require('./GroupPlansData')
+const { isStandaloneAiAddOnPlanCode } = require('./AiHelper')
+const { Subscription } = require('../../models/Subscription')
 
 const MILLISECONDS = 1_000
 /**
@@ -196,7 +196,7 @@ function isInTrial(trialEndsAt) {
   return trialEndsAt.getTime() > Date.now()
 }
 
-export default {
+module.exports = {
   shouldPlanChangeAtTermEnd,
   generateInitialLocalizedGroupPrice,
   isPaidSubscription,
diff --git a/services/web/app/src/Features/Subscription/SubscriptionLocator.mjs b/services/web/app/src/Features/Subscription/SubscriptionLocator.mjs
index 3ded2be604..d4aa4477c9 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionLocator.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionLocator.mjs
@@ -4,9 +4,9 @@
 
 import { callbackifyAll } from '@overleaf/promise-utils'
 
-import { Subscription } from '../../models/Subscription.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
-import { DeletedSubscription } from '../../models/DeletedSubscription.mjs'
+import { Subscription } from '../../models/Subscription.js'
+import SubscriptionHelper from './SubscriptionHelper.js'
+import { DeletedSubscription } from '../../models/DeletedSubscription.js'
 import logger from '@overleaf/logger'
 import { AI_ADD_ON_CODE, isStandaloneAiAddOnPlanCode } from './AiHelper.js'
 import './GroupPlansData.js' // make sure dynamic group plans are loaded
diff --git a/services/web/app/src/Features/Subscription/SubscriptionUpdater.mjs b/services/web/app/src/Features/Subscription/SubscriptionUpdater.mjs
index 6936a55634..39b1cf7025 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionUpdater.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionUpdater.mjs
@@ -1,18 +1,18 @@
 import { db, ObjectId } from '../../infrastructure/mongodb.js'
 import { callbackify } from '@overleaf/promise-utils'
-import { Subscription } from '../../models/Subscription.mjs'
+import { Subscription } from '../../models/Subscription.js'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
 import PlansLocator from './PlansLocator.mjs'
 import FeaturesUpdater from './FeaturesUpdater.mjs'
 import FeaturesHelper from './FeaturesHelper.mjs'
 import AnalyticsManager from '../Analytics/AnalyticsManager.mjs'
-import { DeletedSubscription } from '../../models/DeletedSubscription.mjs'
+import { DeletedSubscription } from '../../models/DeletedSubscription.js'
 import logger from '@overleaf/logger'
 import Features from '../../infrastructure/Features.js'
 import UserAuditLogHandler from '../User/UserAuditLogHandler.mjs'
 import UserUpdater from '../User/UserUpdater.mjs'
 import AccountMappingHelper from '../Analytics/AccountMappingHelper.mjs'
-import { SSOConfig } from '../../models/SSOConfig.mjs'
+import { SSOConfig } from '../../models/SSOConfig.js'
 import mongoose from '../../infrastructure/Mongoose.js'
 import Modules from '../../infrastructure/Modules.js'
 
diff --git a/services/web/app/src/Features/Subscription/SubscriptionViewModelBuilder.mjs b/services/web/app/src/Features/Subscription/SubscriptionViewModelBuilder.mjs
index b4e67c67e8..9fec3a8e5b 100644
--- a/services/web/app/src/Features/Subscription/SubscriptionViewModelBuilder.mjs
+++ b/services/web/app/src/Features/Subscription/SubscriptionViewModelBuilder.mjs
@@ -12,7 +12,7 @@ import PublishersGetter from '../Publishers/PublishersGetter.mjs'
 import sanitizeHtml from 'sanitize-html'
 import _ from 'lodash'
 import async from 'async'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import { callbackify } from '@overleaf/promise-utils'
 import { V1ConnectionError } from '../Errors/Errors.js'
 import FeaturesHelper from './FeaturesHelper.mjs'
diff --git a/services/web/app/src/Features/Subscription/TeamInvitesController.mjs b/services/web/app/src/Features/Subscription/TeamInvitesController.mjs
index 76f8a222dc..58c39bda37 100644
--- a/services/web/app/src/Features/Subscription/TeamInvitesController.mjs
+++ b/services/web/app/src/Features/Subscription/TeamInvitesController.mjs
@@ -4,9 +4,9 @@ import OError from '@overleaf/o-error'
 import TeamInvitesHandler from './TeamInvitesHandler.mjs'
 import SessionManager from '../Authentication/SessionManager.mjs'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
-import SubscriptionHelper from './SubscriptionHelper.mjs'
+import SubscriptionHelper from './SubscriptionHelper.js'
 import ErrorController from '../Errors/ErrorController.mjs'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import UserGetter from '../User/UserGetter.mjs'
 import { expressify } from '@overleaf/promise-utils'
 import HttpErrorHandler from '../Errors/HttpErrorHandler.mjs'
diff --git a/services/web/app/src/Features/Subscription/TeamInvitesHandler.mjs b/services/web/app/src/Features/Subscription/TeamInvitesHandler.mjs
index e1bb4e3abf..79d6aac79a 100644
--- a/services/web/app/src/Features/Subscription/TeamInvitesHandler.mjs
+++ b/services/web/app/src/Features/Subscription/TeamInvitesHandler.mjs
@@ -3,14 +3,14 @@ import crypto from 'node:crypto'
 import settings from '@overleaf/settings'
 import Modules from '../../infrastructure/Modules.js'
 import mongodb from 'mongodb-legacy'
-import { Subscription } from '../../models/Subscription.mjs'
-import { SSOConfig } from '../../models/SSOConfig.mjs'
+import { Subscription } from '../../models/Subscription.js'
+import { SSOConfig } from '../../models/SSOConfig.js'
 import UserGetter from '../User/UserGetter.mjs'
 import SubscriptionLocator from './SubscriptionLocator.mjs'
 import SubscriptionUpdater from './SubscriptionUpdater.mjs'
 import LimitationsManager from './LimitationsManager.mjs'
 import EmailHandler from '../Email/EmailHandler.mjs'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import Errors from '../Errors/Errors.js'
 import { callbackify, callbackifyMultiResult } from '@overleaf/promise-utils'
 import NotificationsBuilder from '../Notifications/NotificationsBuilder.mjs'
diff --git a/services/web/app/src/Features/Subscription/UserFeaturesUpdater.mjs b/services/web/app/src/Features/Subscription/UserFeaturesUpdater.mjs
index 1c96063b8f..0fd61c791a 100644
--- a/services/web/app/src/Features/Subscription/UserFeaturesUpdater.mjs
+++ b/services/web/app/src/Features/Subscription/UserFeaturesUpdater.mjs
@@ -1,4 +1,4 @@
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import { callbackify } from 'node:util'
 import Settings from '@overleaf/settings'
 
diff --git a/services/web/app/src/Features/Survey/SurveyCache.mjs b/services/web/app/src/Features/Survey/SurveyCache.mjs
index 0c9332dcb4..d3552c25d7 100644
--- a/services/web/app/src/Features/Survey/SurveyCache.mjs
+++ b/services/web/app/src/Features/Survey/SurveyCache.mjs
@@ -1,5 +1,5 @@
 import SurveyManager from './SurveyManager.mjs'
-import { Survey } from '../../models/Survey.mjs'
+import { Survey } from '../../models/Survey.js'
 import { CacheLoader } from 'cache-flow'
 
 class SurveyCache extends CacheLoader {
diff --git a/services/web/app/src/Features/Survey/SurveyManager.mjs b/services/web/app/src/Features/Survey/SurveyManager.mjs
index 6ecea42660..cbb23ca0fa 100644
--- a/services/web/app/src/Features/Survey/SurveyManager.mjs
+++ b/services/web/app/src/Features/Survey/SurveyManager.mjs
@@ -1,4 +1,4 @@
-import { Survey } from '../../models/Survey.mjs'
+import { Survey } from '../../models/Survey.js'
 import OError from '@overleaf/o-error'
 
 async function getSurvey() {
diff --git a/services/web/app/src/Features/SystemMessages/SystemMessageManager.mjs b/services/web/app/src/Features/SystemMessages/SystemMessageManager.mjs
index a664a56fba..0da9e302fe 100644
--- a/services/web/app/src/Features/SystemMessages/SystemMessageManager.mjs
+++ b/services/web/app/src/Features/SystemMessages/SystemMessageManager.mjs
@@ -1,4 +1,4 @@
-import { SystemMessage } from '../../models/SystemMessage.mjs'
+import { SystemMessage } from '../../models/SystemMessage.js'
 import { addRequiredCleanupHandlerBeforeDrainingConnections } from '../../infrastructure/GracefulShutdown.js'
 import { callbackifyAll } from '@overleaf/promise-utils'
 import logger from '@overleaf/logger'
diff --git a/services/web/app/src/Features/Tags/TagsHandler.mjs b/services/web/app/src/Features/Tags/TagsHandler.mjs
index 53caadcc68..72bf9f79e0 100644
--- a/services/web/app/src/Features/Tags/TagsHandler.mjs
+++ b/services/web/app/src/Features/Tags/TagsHandler.mjs
@@ -1,4 +1,4 @@
-import { Tag } from '../../models/Tag.mjs'
+import { Tag } from '../../models/Tag.js'
 import { callbackify } from '@overleaf/promise-utils'
 
 const MAX_TAG_LENGTH = 50
diff --git a/services/web/app/src/Features/Templates/TemplatesManager.mjs b/services/web/app/src/Features/Templates/TemplatesManager.mjs
index aefab9ff13..b083cd77c7 100644
--- a/services/web/app/src/Features/Templates/TemplatesManager.mjs
+++ b/services/web/app/src/Features/Templates/TemplatesManager.mjs
@@ -1,4 +1,4 @@
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import ProjectDetailsHandler from '../Project/ProjectDetailsHandler.mjs'
 import ProjectOptionsHandlerModule from '../Project/ProjectOptionsHandler.mjs'
 import ProjectRootDocManagerModule from '../Project/ProjectRootDocManager.mjs'
diff --git a/services/web/app/src/Features/ThirdPartyDataStore/TpdsProjectFlusher.mjs b/services/web/app/src/Features/ThirdPartyDataStore/TpdsProjectFlusher.mjs
index 206682972b..fa27faeda4 100644
--- a/services/web/app/src/Features/ThirdPartyDataStore/TpdsProjectFlusher.mjs
+++ b/services/web/app/src/Features/ThirdPartyDataStore/TpdsProjectFlusher.mjs
@@ -3,7 +3,7 @@ import logger from '@overleaf/logger'
 import DocumentUpdaterHandler from '../DocumentUpdater/DocumentUpdaterHandler.mjs'
 import ProjectGetter from '../Project/ProjectGetter.mjs'
 import ProjectEntityHandler from '../Project/ProjectEntityHandler.mjs'
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import TpdsUpdateSender from './TpdsUpdateSender.mjs'
 import OError from '@overleaf/o-error'
 
diff --git a/services/web/app/src/Features/ThirdPartyDataStore/TpdsUpdateHandler.mjs b/services/web/app/src/Features/ThirdPartyDataStore/TpdsUpdateHandler.mjs
index 599db69109..85842195d9 100644
--- a/services/web/app/src/Features/ThirdPartyDataStore/TpdsUpdateHandler.mjs
+++ b/services/web/app/src/Features/ThirdPartyDataStore/TpdsUpdateHandler.mjs
@@ -8,7 +8,7 @@ import ProjectGetter from '../Project/ProjectGetter.mjs'
 import ProjectHelper from '../Project/ProjectHelper.mjs'
 import ProjectRootDocManager from '../Project/ProjectRootDocManager.mjs'
 import FileTypeManager from '../Uploads/FileTypeManager.mjs'
-import CooldownManager from '../Cooldown/CooldownManager.mjs'
+import CooldownManager from '../Cooldown/CooldownManager.js'
 import Errors from '../Errors/Errors.js'
 import Modules from '../../infrastructure/Modules.js'
 
diff --git a/services/web/app/src/Features/TokenAccess/TokenAccessHandler.mjs b/services/web/app/src/Features/TokenAccess/TokenAccessHandler.mjs
index 88d643707f..05b350f789 100644
--- a/services/web/app/src/Features/TokenAccess/TokenAccessHandler.mjs
+++ b/services/web/app/src/Features/TokenAccess/TokenAccessHandler.mjs
@@ -1,4 +1,4 @@
-import { Project } from '../../models/Project.mjs'
+import { Project } from '../../models/Project.js'
 import PublicAccessLevels from '../Authorization/PublicAccessLevels.mjs'
 import PrivilegeLevels from '../Authorization/PrivilegeLevels.js'
 import mongodb from 'mongodb-legacy'
diff --git a/services/web/app/src/Features/Uploads/ProjectUploadManager.mjs b/services/web/app/src/Features/Uploads/ProjectUploadManager.mjs
index c1fce8f934..4e658903d6 100644
--- a/services/web/app/src/Features/Uploads/ProjectUploadManager.mjs
+++ b/services/web/app/src/Features/Uploads/ProjectUploadManager.mjs
@@ -2,7 +2,7 @@ import Path from 'node:path'
 import fs from 'node:fs'
 import { callbackify } from 'node:util'
 import ArchiveManager from './ArchiveManager.mjs'
-import { Doc } from '../../models/Doc.mjs'
+import { Doc } from '../../models/Doc.js'
 import DocstoreManager from '../Docstore/DocstoreManager.mjs'
 import DocumentHelper from '../Documents/DocumentHelper.mjs'
 import DocumentUpdaterHandler from '../DocumentUpdater/DocumentUpdaterHandler.mjs'
diff --git a/services/web/app/src/Features/User/SAMLIdentityManager.mjs b/services/web/app/src/Features/User/SAMLIdentityManager.mjs
index dd14a29fc2..3d8e84a467 100644
--- a/services/web/app/src/Features/User/SAMLIdentityManager.mjs
+++ b/services/web/app/src/Features/User/SAMLIdentityManager.mjs
@@ -9,7 +9,7 @@ import UserAuditLogHandler from '../User/UserAuditLogHandler.mjs'
 import UserGetter from '../User/UserGetter.mjs'
 import UserUpdater from '../User/UserUpdater.mjs'
 import logger from '@overleaf/logger'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import { promiseMapWithLimit } from '@overleaf/promise-utils'
 
 const { ObjectId } = mongodb
diff --git a/services/web/app/src/Features/User/ThirdPartyIdentityManager.mjs b/services/web/app/src/Features/User/ThirdPartyIdentityManager.mjs
index 5da2254d31..65f3fa62c5 100644
--- a/services/web/app/src/Features/User/ThirdPartyIdentityManager.mjs
+++ b/services/web/app/src/Features/User/ThirdPartyIdentityManager.mjs
@@ -5,7 +5,7 @@ import Errors from '../Errors/Errors.js'
 import _ from 'lodash'
 import logger from '@overleaf/logger'
 import settings from '@overleaf/settings'
-import { User } from '../../../../app/src/models/User.mjs'
+import { User } from '../../../../app/src/models/User.js'
 import { callbackify } from '@overleaf/promise-utils'
 import OError from '@overleaf/o-error'
 
diff --git a/services/web/app/src/Features/User/UserAuditLogHandler.mjs b/services/web/app/src/Features/User/UserAuditLogHandler.mjs
index 919dc30d8a..a617231f43 100644
--- a/services/web/app/src/Features/User/UserAuditLogHandler.mjs
+++ b/services/web/app/src/Features/User/UserAuditLogHandler.mjs
@@ -1,6 +1,6 @@
 import OError from '@overleaf/o-error'
 import logger from '@overleaf/logger'
-import { UserAuditLogEntry } from '../../models/UserAuditLogEntry.mjs'
+import { UserAuditLogEntry } from '../../models/UserAuditLogEntry.js'
 import { callbackify } from 'node:util'
 import SubscriptionLocator from '../Subscription/SubscriptionLocator.mjs'
 
diff --git a/services/web/app/src/Features/User/UserController.mjs b/services/web/app/src/Features/User/UserController.mjs
index 9a21c494d1..a66fedbbb7 100644
--- a/services/web/app/src/Features/User/UserController.mjs
+++ b/services/web/app/src/Features/User/UserController.mjs
@@ -1,7 +1,7 @@
 import UserHandler from './UserHandler.mjs'
 import UserDeleter from './UserDeleter.mjs'
 import UserGetter from './UserGetter.mjs'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import NewsletterManager from '../Newsletter/NewsletterManager.mjs'
 import logger from '@overleaf/logger'
 import metrics from '@overleaf/metrics'
@@ -21,7 +21,7 @@ import { promisify } from 'node:util'
 import { expressify } from '@overleaf/promise-utils'
 import { acceptsJson } from '../../infrastructure/RequestContentTypeDetection.js'
 import Modules from '../../infrastructure/Modules.js'
-import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.mjs'
+import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.js'
 
 async function _sendSecurityAlertClearedSessions(user) {
   const emailOptions = {
diff --git a/services/web/app/src/Features/User/UserCreator.mjs b/services/web/app/src/Features/User/UserCreator.mjs
index 08ed98b455..a5604f1f52 100644
--- a/services/web/app/src/Features/User/UserCreator.mjs
+++ b/services/web/app/src/Features/User/UserCreator.mjs
@@ -2,7 +2,7 @@ import logger from '@overleaf/logger'
 import util from 'node:util'
 import { AffiliationError } from '../Errors/Errors.js'
 import Features from '../../infrastructure/Features.js'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import UserDeleter from './UserDeleter.mjs'
 import UserGetter from './UserGetter.mjs'
 import UserUpdater from './UserUpdater.mjs'
diff --git a/services/web/app/src/Features/User/UserDeleter.mjs b/services/web/app/src/Features/User/UserDeleter.mjs
index 60704ae572..d3657a8696 100644
--- a/services/web/app/src/Features/User/UserDeleter.mjs
+++ b/services/web/app/src/Features/User/UserDeleter.mjs
@@ -1,10 +1,10 @@
 import { callbackify } from 'node:util'
 import logger from '@overleaf/logger'
 import Settings from '@overleaf/settings'
-import { User } from '../../models/User.mjs'
-import { DeletedUser } from '../../models/DeletedUser.mjs'
-import { UserAuditLogEntry } from '../../models/UserAuditLogEntry.mjs'
-import { Feedback } from '../../models/Feedback.mjs'
+import { User } from '../../models/User.js'
+import { DeletedUser } from '../../models/DeletedUser.js'
+import { UserAuditLogEntry } from '../../models/UserAuditLogEntry.js'
+import { Feedback } from '../../models/Feedback.js'
 import NewsletterManager from '../Newsletter/NewsletterManager.mjs'
 import ProjectDeleter from '../Project/ProjectDeleter.mjs'
 import SubscriptionHandler from '../Subscription/SubscriptionHandler.mjs'
diff --git a/services/web/app/src/Features/User/UserEmailsConfirmationHandler.mjs b/services/web/app/src/Features/User/UserEmailsConfirmationHandler.mjs
index 444b4dda56..e85cca3a80 100644
--- a/services/web/app/src/Features/User/UserEmailsConfirmationHandler.mjs
+++ b/services/web/app/src/Features/User/UserEmailsConfirmationHandler.mjs
@@ -1,6 +1,6 @@
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import EmailHandler from '../Email/EmailHandler.mjs'
-import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.mjs'
+import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.js'
 import settings from '@overleaf/settings'
 import Errors from '../Errors/Errors.js'
 import UserUpdater from './UserUpdater.mjs'
diff --git a/services/web/app/src/Features/User/UserEmailsController.mjs b/services/web/app/src/Features/User/UserEmailsController.mjs
index 0a30410740..c63ce4cdd3 100644
--- a/services/web/app/src/Features/User/UserEmailsController.mjs
+++ b/services/web/app/src/Features/User/UserEmailsController.mjs
@@ -6,7 +6,7 @@ import UserGetter from './UserGetter.mjs'
 import UserUpdater from './UserUpdater.mjs'
 import UserSessionsManager from './UserSessionsManager.mjs'
 import EmailHandler from '../Email/EmailHandler.mjs'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import UserEmailsConfirmationHandler from './UserEmailsConfirmationHandler.mjs'
 import InstitutionsAPI from '../Institutions/InstitutionsAPI.mjs'
 import Errors from '../Errors/Errors.js'
diff --git a/services/web/app/src/Features/User/UserGetter.mjs b/services/web/app/src/Features/User/UserGetter.mjs
index c8bce40136..d2cbda1441 100644
--- a/services/web/app/src/Features/User/UserGetter.mjs
+++ b/services/web/app/src/Features/User/UserGetter.mjs
@@ -6,7 +6,7 @@ import InstitutionsAPI from '../Institutions/InstitutionsAPI.mjs'
 import InstitutionsHelper from '../Institutions/InstitutionsHelper.mjs'
 import Errors from '../Errors/Errors.js'
 import Features from '../../infrastructure/Features.js'
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import { normalizeQuery, normalizeMultiQuery } from '../Helpers/Mongo.js'
 import Modules from '../../infrastructure/Modules.js'
 import FeaturesHelper from '../Subscription/FeaturesHelper.mjs'
diff --git a/services/web/app/src/Features/User/UserRegistrationHandler.mjs b/services/web/app/src/Features/User/UserRegistrationHandler.mjs
index 5e77955da2..d01be0acf7 100644
--- a/services/web/app/src/Features/User/UserRegistrationHandler.mjs
+++ b/services/web/app/src/Features/User/UserRegistrationHandler.mjs
@@ -1,4 +1,4 @@
-import { User } from '../../models/User.mjs'
+import { User } from '../../models/User.js'
 import UserCreator from './UserCreator.mjs'
 import UserGetter from './UserGetter.mjs'
 import AuthenticationManager from '../Authentication/AuthenticationManager.mjs'
@@ -6,9 +6,9 @@ import NewsletterManager from '../Newsletter/NewsletterManager.mjs'
 import logger from '@overleaf/logger'
 import crypto from 'node:crypto'
 import EmailHandler from '../Email/EmailHandler.mjs'
-import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.mjs'
+import OneTimeTokenHandler from '../Security/OneTimeTokenHandler.js'
 import settings from '@overleaf/settings'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import { callbackify, callbackifyMultiResult } from '@overleaf/promise-utils'
 import OError from '@overleaf/o-error'
 
diff --git a/services/web/app/src/Features/User/UserUpdater.mjs b/services/web/app/src/Features/User/UserUpdater.mjs
index f45b0456d2..7356790d86 100644
--- a/services/web/app/src/Features/User/UserUpdater.mjs
+++ b/services/web/app/src/Features/User/UserUpdater.mjs
@@ -8,7 +8,7 @@ import InstitutionsAPI from '../Institutions/InstitutionsAPI.mjs'
 import Features from '../../infrastructure/Features.js'
 import FeaturesUpdater from '../Subscription/FeaturesUpdater.mjs'
 import EmailHandler from '../Email/EmailHandler.mjs'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import Errors from '../Errors/Errors.js'
 import NewsletterManager from '../Newsletter/NewsletterManager.mjs'
 import UserAuditLogHandler from './UserAuditLogHandler.mjs'
diff --git a/services/web/app/src/Features/UserMembership/UserMembershipController.mjs b/services/web/app/src/Features/UserMembership/UserMembershipController.mjs
index 381299d910..257dd8ae2c 100644
--- a/services/web/app/src/Features/UserMembership/UserMembershipController.mjs
+++ b/services/web/app/src/Features/UserMembership/UserMembershipController.mjs
@@ -1,10 +1,10 @@
 import SessionManager from '../Authentication/SessionManager.mjs'
 import UserMembershipHandler from './UserMembershipHandler.mjs'
 import Errors from '../Errors/Errors.js'
-import EmailHelper from '../Helpers/EmailHelper.mjs'
+import EmailHelper from '../Helpers/EmailHelper.js'
 import { csvAttachment } from '../../infrastructure/Response.js'
 import UserMembershipErrors from './UserMembershipErrors.mjs'
-import { SSOConfig } from '../../models/SSOConfig.mjs'
+import { SSOConfig } from '../../models/SSOConfig.js'
 import { Parser as CSVParser } from 'json2csv'
 import { expressify } from '@overleaf/promise-utils'
 import PlansLocator from '../Subscription/PlansLocator.mjs'
diff --git a/services/web/app/src/Features/UserMembership/UserMembershipHandler.mjs b/services/web/app/src/Features/UserMembership/UserMembershipHandler.mjs
index f34937df82..6e170f3e6b 100644
--- a/services/web/app/src/Features/UserMembership/UserMembershipHandler.mjs
+++ b/services/web/app/src/Features/UserMembership/UserMembershipHandler.mjs
@@ -1,8 +1,8 @@
 import mongodb from 'mongodb-legacy'
 import { callbackify } from '@overleaf/promise-utils'
-import { Institution } from '../../models/Institution.mjs'
-import { Subscription } from '../../models/Subscription.mjs'
-import { Publisher } from '../../models/Publisher.mjs'
+import { Institution } from '../../models/Institution.js'
+import { Subscription } from '../../models/Subscription.js'
+import { Publisher } from '../../models/Publisher.js'
 import UserMembershipViewModel from './UserMembershipViewModel.mjs'
 import UserGetter from '../User/UserGetter.mjs'
 import UserMembershipErrors from './UserMembershipErrors.mjs'
diff --git a/services/web/app/src/Features/UserMembership/UserMembershipsHandler.mjs b/services/web/app/src/Features/UserMembership/UserMembershipsHandler.mjs
index fc1c6d0b8e..3e5239cdae 100644
--- a/services/web/app/src/Features/UserMembership/UserMembershipsHandler.mjs
+++ b/services/web/app/src/Features/UserMembership/UserMembershipsHandler.mjs
@@ -13,9 +13,9 @@ import async from 'async'
 
 import { promisifyAll } from '@overleaf/promise-utils'
 import UserMembershipEntityConfigs from './UserMembershipEntityConfigs.mjs'
-import * as InstitutionModel from '../../models/Institution.mjs'
-import * as SubscriptionModel from '../../models/Subscription.mjs'
-import * as PublisherModel from '../../models/Publisher.mjs'
+import InstitutionModel from '../../models/Institution.js'
+import SubscriptionModel from '../../models/Subscription.js'
+import PublisherModel from '../../models/Publisher.js'
 
 const EntityModels = {
   Institution: InstitutionModel.Institution,
diff --git a/services/web/app/src/models/DeletedProject.mjs b/services/web/app/src/models/DeletedProject.js
similarity index 79%
rename from services/web/app/src/models/DeletedProject.mjs
rename to services/web/app/src/models/DeletedProject.js
index 652c052849..c1f6ce9e2c 100644
--- a/services/web/app/src/models/DeletedProject.mjs
+++ b/services/web/app/src/models/DeletedProject.js
@@ -1,10 +1,10 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import { ProjectSchema } from './Project.mjs'
+const mongoose = require('../infrastructure/Mongoose')
+const { ProjectSchema } = require('./Project')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const DeleterDataSchema = new Schema({
+const DeleterDataSchema = new Schema({
   deleterId: { type: ObjectId, ref: 'User' },
   deleterIpAddress: { type: String },
   deletedAt: { type: Date },
@@ -30,7 +30,5 @@ const DeletedProjectSchema = new Schema(
   { collection: 'deletedProjects', minimize: false }
 )
 
-export const DeletedProject = mongoose.model(
-  'DeletedProject',
-  DeletedProjectSchema
-)
+exports.DeletedProject = mongoose.model('DeletedProject', DeletedProjectSchema)
+exports.DeletedProjectSchema = DeletedProjectSchema
diff --git a/services/web/app/src/models/DeletedSubscription.mjs b/services/web/app/src/models/DeletedSubscription.js
similarity index 66%
rename from services/web/app/src/models/DeletedSubscription.mjs
rename to services/web/app/src/models/DeletedSubscription.js
index b37d2f1ea6..10b649d9be 100644
--- a/services/web/app/src/models/DeletedSubscription.mjs
+++ b/services/web/app/src/models/DeletedSubscription.js
@@ -1,10 +1,10 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import { SubscriptionSchema } from './Subscription.mjs'
+const mongoose = require('../infrastructure/Mongoose')
+const { SubscriptionSchema } = require('./Subscription')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const DeleterDataSchema = new Schema(
+const DeleterDataSchema = new Schema(
   {
     deleterId: { type: ObjectId, ref: 'User' },
     deleterIpAddress: { type: String },
@@ -26,7 +26,9 @@ const DeletedSubscriptionSchema = new Schema(
   { collection: 'deletedSubscriptions', minimize: false }
 )
 
-export const DeletedSubscription = mongoose.model(
+exports.DeletedSubscription = mongoose.model(
   'DeletedSubscription',
   DeletedSubscriptionSchema
 )
+
+exports.DeletedSubscriptionSchema = DeletedSubscriptionSchema
diff --git a/services/web/app/src/models/DeletedUser.mjs b/services/web/app/src/models/DeletedUser.js
similarity index 73%
rename from services/web/app/src/models/DeletedUser.mjs
rename to services/web/app/src/models/DeletedUser.js
index 17f221c3ce..5d20f9bb40 100644
--- a/services/web/app/src/models/DeletedUser.mjs
+++ b/services/web/app/src/models/DeletedUser.js
@@ -1,5 +1,5 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import { UserSchema } from './User.mjs'
+const mongoose = require('../infrastructure/Mongoose')
+const { UserSchema } = require('./User')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
@@ -18,7 +18,7 @@ const DeleterDataSchema = new Schema({
   deletedUserOverleafId: { type: Number },
 })
 
-export const DeletedUserSchema = new Schema(
+const DeletedUserSchema = new Schema(
   {
     deleterData: DeleterDataSchema,
     user: UserSchema,
@@ -26,4 +26,6 @@ export const DeletedUserSchema = new Schema(
   { collection: 'deletedUsers', minimize: false }
 )
 
-export const DeletedUser = mongoose.model('DeletedUser', DeletedUserSchema)
+exports.DeletedUser = mongoose.model('DeletedUser', DeletedUserSchema)
+
+exports.DeletedUserSchema = DeletedUserSchema
diff --git a/services/web/app/src/models/Doc.js b/services/web/app/src/models/Doc.js
new file mode 100644
index 0000000000..9f38ac0975
--- /dev/null
+++ b/services/web/app/src/models/Doc.js
@@ -0,0 +1,14 @@
+const mongoose = require('../infrastructure/Mongoose')
+
+const { Schema } = mongoose
+
+const DocSchema = new Schema(
+  {
+    name: { type: String, default: 'new doc' },
+  },
+  { minimize: false }
+)
+
+exports.Doc = mongoose.model('Doc', DocSchema)
+
+exports.DocSchema = DocSchema
diff --git a/services/web/app/src/models/Doc.mjs b/services/web/app/src/models/Doc.mjs
deleted file mode 100644
index c06ff3b775..0000000000
--- a/services/web/app/src/models/Doc.mjs
+++ /dev/null
@@ -1,12 +0,0 @@
-import mongoose from '../infrastructure/Mongoose.js'
-
-const { Schema } = mongoose
-
-export const DocSchema = new Schema(
-  {
-    name: { type: String, default: 'new doc' },
-  },
-  { minimize: false }
-)
-
-export const Doc = mongoose.model('Doc', DocSchema)
diff --git a/services/web/app/src/models/DocSnapshot.mjs b/services/web/app/src/models/DocSnapshot.js
similarity index 70%
rename from services/web/app/src/models/DocSnapshot.mjs
rename to services/web/app/src/models/DocSnapshot.js
index 0a5793f818..b851d4a94f 100644
--- a/services/web/app/src/models/DocSnapshot.mjs
+++ b/services/web/app/src/models/DocSnapshot.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
@@ -15,4 +15,4 @@ const DocSnapshotSchema = new Schema(
   { collection: 'docSnapshots', minimize: false }
 )
 
-export const DocSnapshot = mongoose.model('DocSnapshot', DocSnapshotSchema)
+exports.DocSnapshot = mongoose.model('DocSnapshot', DocSnapshotSchema)
diff --git a/services/web/app/src/models/Feedback.mjs b/services/web/app/src/models/Feedback.js
similarity index 59%
rename from services/web/app/src/models/Feedback.mjs
rename to services/web/app/src/models/Feedback.js
index ef583a0ac9..8b6382114f 100644
--- a/services/web/app/src/models/Feedback.mjs
+++ b/services/web/app/src/models/Feedback.js
@@ -1,8 +1,8 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const FeedbackSchema = new Schema(
+const FeedbackSchema = new Schema(
   {
     userId: {
       type: ObjectId,
@@ -20,4 +20,5 @@ export const FeedbackSchema = new Schema(
   { minimize: false }
 )
 
-export const Feedback = mongoose.model('Feedback', FeedbackSchema)
+exports.Feedback = mongoose.model('Feedback', FeedbackSchema)
+exports.FeedbackSchema = FeedbackSchema
diff --git a/services/web/app/src/models/File.mjs b/services/web/app/src/models/File.js
similarity index 67%
rename from services/web/app/src/models/File.mjs
rename to services/web/app/src/models/File.js
index 60742e6797..5a7c772e3e 100644
--- a/services/web/app/src/models/File.mjs
+++ b/services/web/app/src/models/File.js
@@ -1,8 +1,8 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
-export const FileSchema = new Schema(
+const FileSchema = new Schema(
   {
     name: {
       type: String,
@@ -23,4 +23,5 @@ export const FileSchema = new Schema(
   { minimize: false }
 )
 
-export const File = mongoose.model('File', FileSchema)
+exports.File = mongoose.model('File', FileSchema)
+exports.FileSchema = FileSchema
diff --git a/services/web/app/src/models/Folder.js b/services/web/app/src/models/Folder.js
new file mode 100644
index 0000000000..52312e90d8
--- /dev/null
+++ b/services/web/app/src/models/Folder.js
@@ -0,0 +1,21 @@
+const mongoose = require('../infrastructure/Mongoose')
+const { DocSchema } = require('./Doc')
+const { FileSchema } = require('./File')
+
+const { Schema } = mongoose
+
+const FolderSchema = new Schema(
+  {
+    name: { type: String, default: 'new folder' },
+  },
+  { minimize: false }
+)
+
+FolderSchema.add({
+  docs: [DocSchema],
+  fileRefs: [FileSchema],
+  folders: [FolderSchema],
+})
+
+exports.Folder = mongoose.model('Folder', FolderSchema)
+exports.FolderSchema = FolderSchema
diff --git a/services/web/app/src/models/Folder.mjs b/services/web/app/src/models/Folder.mjs
deleted file mode 100644
index 7ac893f868..0000000000
--- a/services/web/app/src/models/Folder.mjs
+++ /dev/null
@@ -1,20 +0,0 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import { DocSchema } from './Doc.mjs'
-import { FileSchema } from './File.mjs'
-
-const { Schema } = mongoose
-
-export const FolderSchema = new Schema(
-  {
-    name: { type: String, default: 'new folder' },
-  },
-  { minimize: false }
-)
-
-FolderSchema.add({
-  docs: [DocSchema],
-  fileRefs: [FileSchema],
-  folders: [FolderSchema],
-})
-
-export const Folder = mongoose.model('Folder', FolderSchema)
diff --git a/services/web/app/src/models/GlobalMetric.js b/services/web/app/src/models/GlobalMetric.js
new file mode 100644
index 0000000000..824c1478a2
--- /dev/null
+++ b/services/web/app/src/models/GlobalMetric.js
@@ -0,0 +1,19 @@
+const mongoose = require('../infrastructure/Mongoose')
+const { Schema } = mongoose
+
+const GlobalMetricSchema = new Schema(
+  {
+    _id: { type: String, required: true },
+    value: {
+      type: Number,
+      default: 0,
+    },
+  },
+  {
+    collection: 'globalMetrics',
+    minimize: false,
+  }
+)
+
+exports.GlobalMetric = mongoose.model('GlobalMetric', GlobalMetricSchema)
+exports.GlobalMetricSchema = GlobalMetricSchema
diff --git a/services/web/app/src/models/GlobalMetric.mjs b/services/web/app/src/models/GlobalMetric.mjs
deleted file mode 100644
index de019d40b2..0000000000
--- a/services/web/app/src/models/GlobalMetric.mjs
+++ /dev/null
@@ -1,18 +0,0 @@
-import mongoose from '../infrastructure/Mongoose.js'
-const { Schema } = mongoose
-
-export const GlobalMetricSchema = new Schema(
-  {
-    _id: { type: String, required: true },
-    value: {
-      type: Number,
-      default: 0,
-    },
-  },
-  {
-    collection: 'globalMetrics',
-    minimize: false,
-  }
-)
-
-export const GlobalMetric = mongoose.model('GlobalMetric', GlobalMetricSchema)
diff --git a/services/web/app/src/models/GroupAuditLogEntry.mjs b/services/web/app/src/models/GroupAuditLogEntry.js
similarity index 66%
rename from services/web/app/src/models/GroupAuditLogEntry.mjs
rename to services/web/app/src/models/GroupAuditLogEntry.js
index 5d834df350..3bda4ebf95 100644
--- a/services/web/app/src/models/GroupAuditLogEntry.mjs
+++ b/services/web/app/src/models/GroupAuditLogEntry.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const GroupAuditLogEntrySchema = new Schema(
+const GroupAuditLogEntrySchema = new Schema(
   {
     groupId: { type: Schema.Types.ObjectId, index: true },
     info: { type: Object },
@@ -16,7 +16,8 @@ export const GroupAuditLogEntrySchema = new Schema(
   }
 )
 
-export const GroupAuditLogEntry = mongoose.model(
+exports.GroupAuditLogEntry = mongoose.model(
   'GroupAuditLogEntry',
   GroupAuditLogEntrySchema
 )
+exports.GroupAuditLogEntrySchema = GroupAuditLogEntrySchema
diff --git a/services/web/app/src/models/GroupPolicy.mjs b/services/web/app/src/models/GroupPolicy.js
similarity index 83%
rename from services/web/app/src/models/GroupPolicy.mjs
rename to services/web/app/src/models/GroupPolicy.js
index c38488aa63..55728a2415 100644
--- a/services/web/app/src/models/GroupPolicy.mjs
+++ b/services/web/app/src/models/GroupPolicy.js
@@ -1,8 +1,8 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
-export const GroupPolicySchema = new Schema(
+const GroupPolicySchema = new Schema(
   {
     // User can't delete their own account
     userCannotDeleteOwnAccount: Boolean,
@@ -34,4 +34,5 @@ export const GroupPolicySchema = new Schema(
   { minimize: false }
 )
 
-export const GroupPolicy = mongoose.model('GroupPolicy', GroupPolicySchema)
+exports.GroupPolicy = mongoose.model('GroupPolicy', GroupPolicySchema)
+exports.GroupPolicySchema = GroupPolicySchema
diff --git a/services/web/app/src/models/Institution.mjs b/services/web/app/src/models/Institution.js
similarity index 76%
rename from services/web/app/src/models/Institution.mjs
rename to services/web/app/src/models/Institution.js
index a51dbd3f0b..fd18cf33c2 100644
--- a/services/web/app/src/models/Institution.mjs
+++ b/services/web/app/src/models/Institution.js
@@ -1,12 +1,12 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import settings from '@overleaf/settings'
-import logger from '@overleaf/logger'
-import { promisify } from '@overleaf/promise-utils'
-import { fetchJson } from '@overleaf/fetch-utils'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 const { ObjectId } = Schema
+const settings = require('@overleaf/settings')
+const logger = require('@overleaf/logger')
+const { promisify } = require('@overleaf/promise-utils')
+const { fetchJson } = require('@overleaf/fetch-utils')
 
-export const InstitutionSchema = new Schema(
+const InstitutionSchema = new Schema(
   {
     v1Id: { type: Number, required: true },
     managerIds: [{ type: ObjectId, ref: 'User' }],
@@ -45,4 +45,5 @@ InstitutionSchema.method(
   promisify(InstitutionSchema.methods.fetchV1Data)
 )
 
-export const Institution = mongoose.model('Institution', InstitutionSchema)
+exports.Institution = mongoose.model('Institution', InstitutionSchema)
+exports.InstitutionSchema = InstitutionSchema
diff --git a/services/web/app/src/models/OauthAccessToken.mjs b/services/web/app/src/models/OauthAccessToken.js
similarity index 73%
rename from services/web/app/src/models/OauthAccessToken.mjs
rename to services/web/app/src/models/OauthAccessToken.js
index d3a9edc9fe..8b3dbc8926 100644
--- a/services/web/app/src/models/OauthAccessToken.mjs
+++ b/services/web/app/src/models/OauthAccessToken.js
@@ -1,9 +1,9 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const OauthAccessTokenSchema = new Schema(
+const OauthAccessTokenSchema = new Schema(
   {
     accessToken: String,
     accessTokenPartial: String,
@@ -24,7 +24,9 @@ export const OauthAccessTokenSchema = new Schema(
   }
 )
 
-export const OauthAccessToken = mongoose.model(
+exports.OauthAccessToken = mongoose.model(
   'OauthAccessToken',
   OauthAccessTokenSchema
 )
+
+exports.OauthAccessTokenSchema = OauthAccessTokenSchema
diff --git a/services/web/app/src/models/OauthApplication.mjs b/services/web/app/src/models/OauthApplication.js
similarity index 61%
rename from services/web/app/src/models/OauthApplication.mjs
rename to services/web/app/src/models/OauthApplication.js
index 83ff51fa55..d7bd181fd6 100644
--- a/services/web/app/src/models/OauthApplication.mjs
+++ b/services/web/app/src/models/OauthApplication.js
@@ -1,8 +1,8 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
-export const OauthApplicationSchema = new Schema(
+const OauthApplicationSchema = new Schema(
   {
     id: String,
     clientSecret: String,
@@ -18,7 +18,9 @@ export const OauthApplicationSchema = new Schema(
   }
 )
 
-export const OauthApplication = mongoose.model(
+exports.OauthApplication = mongoose.model(
   'OauthApplication',
   OauthApplicationSchema
 )
+
+exports.OauthApplicationSchema = OauthApplicationSchema
diff --git a/services/web/app/src/models/OauthAuthorizationCode.mjs b/services/web/app/src/models/OauthAuthorizationCode.js
similarity index 68%
rename from services/web/app/src/models/OauthAuthorizationCode.mjs
rename to services/web/app/src/models/OauthAuthorizationCode.js
index 9750750f1a..6b9822377f 100644
--- a/services/web/app/src/models/OauthAuthorizationCode.mjs
+++ b/services/web/app/src/models/OauthAuthorizationCode.js
@@ -1,9 +1,9 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const OauthAuthorizationCodeSchema = new Schema(
+const OauthAuthorizationCodeSchema = new Schema(
   {
     authorizationCode: String,
     expiresAt: Date,
@@ -20,7 +20,9 @@ export const OauthAuthorizationCodeSchema = new Schema(
   }
 )
 
-export const OauthAuthorizationCode = mongoose.model(
+exports.OauthAuthorizationCode = mongoose.model(
   'OauthAuthorizationCode',
   OauthAuthorizationCodeSchema
 )
+
+exports.OauthAuthorizationCodeSchema = OauthAuthorizationCodeSchema
diff --git a/services/web/app/src/models/OnboardingDataCollection.mjs b/services/web/app/src/models/OnboardingDataCollection.js
similarity index 76%
rename from services/web/app/src/models/OnboardingDataCollection.mjs
rename to services/web/app/src/models/OnboardingDataCollection.js
index edab377914..e0625f71fc 100644
--- a/services/web/app/src/models/OnboardingDataCollection.mjs
+++ b/services/web/app/src/models/OnboardingDataCollection.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const OnboardingDataCollectionSchema = new Schema(
+const OnboardingDataCollectionSchema = new Schema(
   {
     firstName: { type: String, default: null },
     lastName: { type: String, default: null },
@@ -24,12 +24,10 @@ export const OnboardingDataCollectionSchema = new Schema(
   }
 )
 
-export const OnboardingDataCollection = mongoose.model(
-  'OnboardingDataCollection',
-  OnboardingDataCollectionSchema
-)
-
-export default {
-  OnboardingDataCollection,
+module.exports = {
+  OnboardingDataCollection: mongoose.model(
+    'OnboardingDataCollection',
+    OnboardingDataCollectionSchema
+  ),
   OnboardingDataCollectionSchema,
 }
diff --git a/services/web/app/src/models/Project.mjs b/services/web/app/src/models/Project.js
similarity index 92%
rename from services/web/app/src/models/Project.mjs
rename to services/web/app/src/models/Project.js
index fec4769008..69db145038 100644
--- a/services/web/app/src/models/Project.mjs
+++ b/services/web/app/src/models/Project.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import _ from 'lodash'
-import { FolderSchema } from './Folder.mjs'
-import Errors from '../Features/Errors/Errors.js'
+const mongoose = require('../infrastructure/Mongoose')
+const _ = require('lodash')
+const { FolderSchema } = require('./Folder')
+const Errors = require('../Features/Errors/Errors')
 
 const ConcreteObjectId = mongoose.Types.ObjectId
 const { Schema } = mongoose
@@ -12,7 +12,7 @@ const DeletedDocSchema = new Schema({
   deletedAt: { type: Date },
 })
 
-export const ProjectSchema = new Schema(
+const ProjectSchema = new Schema(
   {
     name: { type: String, default: 'new project' },
     lastUpdated: {
@@ -127,4 +127,5 @@ function applyToAllFilesRecursivly(folder, fun) {
 }
 ProjectSchema.statics.applyToAllFilesRecursivly = applyToAllFilesRecursivly
 
-export const Project = mongoose.model('Project', ProjectSchema)
+exports.Project = mongoose.model('Project', ProjectSchema)
+exports.ProjectSchema = ProjectSchema
diff --git a/services/web/app/src/models/ProjectAuditLogEntry.mjs b/services/web/app/src/models/ProjectAuditLogEntry.js
similarity index 70%
rename from services/web/app/src/models/ProjectAuditLogEntry.mjs
rename to services/web/app/src/models/ProjectAuditLogEntry.js
index 7e668a60e3..fb4a950a40 100644
--- a/services/web/app/src/models/ProjectAuditLogEntry.mjs
+++ b/services/web/app/src/models/ProjectAuditLogEntry.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const ProjectAuditLogEntrySchema = new Schema(
+const ProjectAuditLogEntrySchema = new Schema(
   {
     projectId: { type: Schema.Types.ObjectId, index: true },
     managedSubscriptionId: { type: Schema.Types.ObjectId, index: true },
@@ -17,7 +17,8 @@ export const ProjectAuditLogEntrySchema = new Schema(
   }
 )
 
-export const ProjectAuditLogEntry = mongoose.model(
+exports.ProjectAuditLogEntry = mongoose.model(
   'ProjectAuditLogEntry',
   ProjectAuditLogEntrySchema
 )
+exports.ProjectAuditLogEntrySchema = ProjectAuditLogEntrySchema
diff --git a/services/web/app/src/models/ProjectHistoryFailure.mjs b/services/web/app/src/models/ProjectHistoryFailure.js
similarity index 80%
rename from services/web/app/src/models/ProjectHistoryFailure.mjs
rename to services/web/app/src/models/ProjectHistoryFailure.js
index f584945ce5..7bfd1a3d85 100644
--- a/services/web/app/src/models/ProjectHistoryFailure.mjs
+++ b/services/web/app/src/models/ProjectHistoryFailure.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
@@ -18,7 +18,7 @@ const ProjectHistoryFailureSchema = new Schema(
   { collection: 'projectHistoryFailures', minimize: false }
 )
 
-export const ProjectHistoryFailure = mongoose.model(
+exports.ProjectHistoryFailure = mongoose.model(
   'ProjectHistoryFailure',
   ProjectHistoryFailureSchema
 )
diff --git a/services/web/app/src/models/ProjectInvite.mjs b/services/web/app/src/models/ProjectInvite.js
similarity index 64%
rename from services/web/app/src/models/ProjectInvite.mjs
rename to services/web/app/src/models/ProjectInvite.js
index 879cd9f49c..a7bfbad1e0 100644
--- a/services/web/app/src/models/ProjectInvite.mjs
+++ b/services/web/app/src/models/ProjectInvite.js
@@ -1,9 +1,9 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const EXPIRY_IN_SECONDS = 60 * 60 * 24 * 30
+const EXPIRY_IN_SECONDS = 60 * 60 * 24 * 30
 
 const ExpiryDate = function () {
   const timestamp = new Date()
@@ -11,7 +11,7 @@ const ExpiryDate = function () {
   return timestamp
 }
 
-export const ProjectInviteSchema = new Schema(
+const ProjectInviteSchema = new Schema(
   {
     email: String,
     tokenHmac: String,
@@ -31,7 +31,6 @@ export const ProjectInviteSchema = new Schema(
   }
 )
 
-export const ProjectInvite = mongoose.model(
-  'ProjectInvite',
-  ProjectInviteSchema
-)
+exports.ProjectInvite = mongoose.model('ProjectInvite', ProjectInviteSchema)
+exports.ProjectInviteSchema = ProjectInviteSchema
+exports.EXPIRY_IN_SECONDS = EXPIRY_IN_SECONDS
diff --git a/services/web/app/src/models/Publisher.mjs b/services/web/app/src/models/Publisher.js
similarity index 77%
rename from services/web/app/src/models/Publisher.mjs
rename to services/web/app/src/models/Publisher.js
index 9bbbd24e54..e9e10e49c0 100644
--- a/services/web/app/src/models/Publisher.mjs
+++ b/services/web/app/src/models/Publisher.js
@@ -1,11 +1,11 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import settings from '@overleaf/settings'
-import logger from '@overleaf/logger'
-import request from 'request'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 const { ObjectId } = Schema
+const settings = require('@overleaf/settings')
+const logger = require('@overleaf/logger')
+const request = require('request')
 
-export const PublisherSchema = new Schema(
+const PublisherSchema = new Schema(
   {
     slug: { type: String, required: true },
     managerIds: [{ type: ObjectId, ref: 'User' }],
@@ -46,4 +46,5 @@ PublisherSchema.method('fetchV1Data', function (callback) {
   )
 })
 
-export const Publisher = mongoose.model('Publisher', PublisherSchema)
+exports.Publisher = mongoose.model('Publisher', PublisherSchema)
+exports.PublisherSchema = PublisherSchema
diff --git a/services/web/app/src/models/SSOConfig.mjs b/services/web/app/src/models/SSOConfig.js
similarity index 73%
rename from services/web/app/src/models/SSOConfig.mjs
rename to services/web/app/src/models/SSOConfig.js
index 6db3584619..0349d8a651 100644
--- a/services/web/app/src/models/SSOConfig.mjs
+++ b/services/web/app/src/models/SSOConfig.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const SSOConfigSchema = new Schema(
+const SSOConfigSchema = new Schema(
   {
     entryPoint: { type: String, required: true },
     certificates: { type: Array, default: [''], required: true },
@@ -20,4 +20,5 @@ export const SSOConfigSchema = new Schema(
   }
 )
 
-export const SSOConfig = mongoose.model('SSOConfig', SSOConfigSchema)
+exports.SSOConfig = mongoose.model('SSOConfig', SSOConfigSchema)
+exports.SSOConfigSchema = SSOConfigSchema
diff --git a/services/web/app/src/models/SamlCache.js b/services/web/app/src/models/SamlCache.js
new file mode 100644
index 0000000000..185fe61422
--- /dev/null
+++ b/services/web/app/src/models/SamlCache.js
@@ -0,0 +1,16 @@
+const mongoose = require('../infrastructure/Mongoose')
+const { Schema } = mongoose
+
+const SamlCacheSchema = new Schema(
+  {
+    createdAt: { type: Date },
+    requestId: { type: String },
+  },
+  {
+    collection: 'samlCache',
+    minimize: false,
+  }
+)
+
+exports.SamlCache = mongoose.model('SamlCache', SamlCacheSchema)
+exports.SamlCacheSchema = SamlCacheSchema
diff --git a/services/web/app/src/models/SamlCache.mjs b/services/web/app/src/models/SamlCache.mjs
deleted file mode 100644
index a58a76ea68..0000000000
--- a/services/web/app/src/models/SamlCache.mjs
+++ /dev/null
@@ -1,15 +0,0 @@
-import mongoose from '../infrastructure/Mongoose.js'
-const { Schema } = mongoose
-
-export const SamlCacheSchema = new Schema(
-  {
-    createdAt: { type: Date },
-    requestId: { type: String },
-  },
-  {
-    collection: 'samlCache',
-    minimize: false,
-  }
-)
-
-export const SamlCache = mongoose.model('SamlCache', SamlCacheSchema)
diff --git a/services/web/app/src/models/SamlLog.mjs b/services/web/app/src/models/SamlLog.js
similarity index 69%
rename from services/web/app/src/models/SamlLog.mjs
rename to services/web/app/src/models/SamlLog.js
index 929c7b2600..52889770f0 100644
--- a/services/web/app/src/models/SamlLog.mjs
+++ b/services/web/app/src/models/SamlLog.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const SamlLogSchema = new Schema(
+const SamlLogSchema = new Schema(
   {
     createdAt: { type: Date, default: () => new Date() },
     data: { type: Object },
@@ -18,4 +18,5 @@ export const SamlLogSchema = new Schema(
   }
 )
 
-export const SamlLog = mongoose.model('SamlLog', SamlLogSchema)
+exports.SamlLog = mongoose.model('SamlLog', SamlLogSchema)
+exports.SamlLogSchema = SamlLogSchema
diff --git a/services/web/app/src/models/SplitTest.mjs b/services/web/app/src/models/SplitTest.js
similarity index 95%
rename from services/web/app/src/models/SplitTest.mjs
rename to services/web/app/src/models/SplitTest.js
index b15c81adb4..c605693bfa 100644
--- a/services/web/app/src/models/SplitTest.mjs
+++ b/services/web/app/src/models/SplitTest.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
@@ -112,7 +112,7 @@ const VersionSchema = new Schema(
   { _id: false }
 )
 
-export const SplitTestSchema = new Schema(
+const SplitTestSchema = new Schema(
   {
     name: {
       type: String,
@@ -178,4 +178,7 @@ export const SplitTestSchema = new Schema(
   { minimize: false }
 )
 
-export const SplitTest = mongoose.model('SplitTest', SplitTestSchema)
+module.exports = {
+  SplitTest: mongoose.model('SplitTest', SplitTestSchema),
+  SplitTestSchema,
+}
diff --git a/services/web/app/src/models/Subscription.mjs b/services/web/app/src/models/Subscription.js
similarity index 91%
rename from services/web/app/src/models/Subscription.mjs
rename to services/web/app/src/models/Subscription.js
index 416f637c6f..c7606d39ea 100644
--- a/services/web/app/src/models/Subscription.mjs
+++ b/services/web/app/src/models/Subscription.js
@@ -1,10 +1,10 @@
-import mongoose from '../infrastructure/Mongoose.js'
-import { TeamInviteSchema } from './TeamInvite.mjs'
+const mongoose = require('../infrastructure/Mongoose')
+const { TeamInviteSchema } = require('./TeamInvite')
 
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
-export const SubscriptionSchema = new Schema(
+const SubscriptionSchema = new Schema(
   {
     admin_id: {
       type: ObjectId,
@@ -123,4 +123,5 @@ SubscriptionSchema.method('fetchV1Data', function (callback) {
   callback(null, this)
 })
 
-export const Subscription = mongoose.model('Subscription', SubscriptionSchema)
+exports.Subscription = mongoose.model('Subscription', SubscriptionSchema)
+exports.SubscriptionSchema = SubscriptionSchema
diff --git a/services/web/app/src/models/Survey.mjs b/services/web/app/src/models/Survey.js
similarity index 86%
rename from services/web/app/src/models/Survey.mjs
rename to services/web/app/src/models/Survey.js
index 3c98e19fb8..01068ef49a 100644
--- a/services/web/app/src/models/Survey.mjs
+++ b/services/web/app/src/models/Survey.js
@@ -1,11 +1,11 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
 const MIN_NAME_LENGTH = 3
 const MAX_NAME_LENGTH = 200
 const NAME_REGEX = /^[a-z0-9-]+$/
 
-export const SurveySchema = new Schema(
+const SurveySchema = new Schema(
   {
     name: {
       type: String,
@@ -62,4 +62,7 @@ export const SurveySchema = new Schema(
   }
 )
 
-export const Survey = mongoose.model('Survey', SurveySchema)
+module.exports = {
+  Survey: mongoose.model('Survey', SurveySchema),
+  SurveySchema,
+}
diff --git a/services/web/app/src/models/SystemMessage.mjs b/services/web/app/src/models/SystemMessage.js
similarity index 51%
rename from services/web/app/src/models/SystemMessage.mjs
rename to services/web/app/src/models/SystemMessage.js
index 4191801f4e..c3e37d00c6 100644
--- a/services/web/app/src/models/SystemMessage.mjs
+++ b/services/web/app/src/models/SystemMessage.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 
 const { Schema } = mongoose
 
@@ -9,7 +9,4 @@ const SystemMessageSchema = new Schema(
   { minimize: false }
 )
 
-export const SystemMessage = mongoose.model(
-  'SystemMessage',
-  SystemMessageSchema
-)
+exports.SystemMessage = mongoose.model('SystemMessage', SystemMessageSchema)
diff --git a/services/web/app/src/models/Tag.mjs b/services/web/app/src/models/Tag.js
similarity index 76%
rename from services/web/app/src/models/Tag.mjs
rename to services/web/app/src/models/Tag.js
index 7824d95d53..8e0eb115dc 100644
--- a/services/web/app/src/models/Tag.mjs
+++ b/services/web/app/src/models/Tag.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
 const COLOR_REGEX = /^#[a-fA-F0-9]{6}$/
@@ -6,7 +6,7 @@ const COLOR_REGEX = /^#[a-fA-F0-9]{6}$/
 // Note that for legacy reasons, user_id and project_ids are plain strings,
 // not ObjectIds.
 
-export const TagSchema = new Schema(
+const TagSchema = new Schema(
   {
     user_id: { type: String, required: true },
     name: { type: String, required: true },
@@ -24,4 +24,5 @@ export const TagSchema = new Schema(
   { minimize: false }
 )
 
-export const Tag = mongoose.model('Tag', TagSchema)
+exports.Tag = mongoose.model('Tag', TagSchema)
+exports.TagSchema = TagSchema
diff --git a/services/web/app/src/models/TeamInvite.js b/services/web/app/src/models/TeamInvite.js
new file mode 100644
index 0000000000..b115d27261
--- /dev/null
+++ b/services/web/app/src/models/TeamInvite.js
@@ -0,0 +1,16 @@
+const mongoose = require('../infrastructure/Mongoose')
+
+const { Schema } = mongoose
+
+const TeamInviteSchema = new Schema(
+  {
+    email: { type: String, required: true },
+    token: { type: String },
+    inviterName: { type: String },
+    sentAt: { type: Date },
+  },
+  { minimize: false }
+)
+
+exports.TeamInvite = mongoose.model('TeamInvite', TeamInviteSchema)
+exports.TeamInviteSchema = TeamInviteSchema
diff --git a/services/web/app/src/models/TeamInvite.mjs b/services/web/app/src/models/TeamInvite.mjs
deleted file mode 100644
index dfa31c09ff..0000000000
--- a/services/web/app/src/models/TeamInvite.mjs
+++ /dev/null
@@ -1,15 +0,0 @@
-import mongoose from '../infrastructure/Mongoose.js'
-
-const { Schema } = mongoose
-
-export const TeamInviteSchema = new Schema(
-  {
-    email: { type: String, required: true },
-    token: { type: String },
-    inviterName: { type: String },
-    sentAt: { type: Date },
-  },
-  { minimize: false }
-)
-
-export const TeamInvite = mongoose.model('TeamInvite', TeamInviteSchema)
diff --git a/services/web/app/src/models/User.mjs b/services/web/app/src/models/User.js
similarity index 96%
rename from services/web/app/src/models/User.mjs
rename to services/web/app/src/models/User.js
index 6bfebfc3a5..bdf8a4c4ed 100644
--- a/services/web/app/src/models/User.mjs
+++ b/services/web/app/src/models/User.js
@@ -1,6 +1,6 @@
-import Settings from '@overleaf/settings'
-import mongoose from '../infrastructure/Mongoose.js'
-import TokenGenerator from '../Features/TokenGenerator/TokenGenerator.js'
+const Settings = require('@overleaf/settings')
+const mongoose = require('../infrastructure/Mongoose')
+const TokenGenerator = require('../Features/TokenGenerator/TokenGenerator')
 const { Schema } = mongoose
 const { ObjectId } = Schema
 
@@ -8,7 +8,7 @@ const { ObjectId } = Schema
 const MAX_EMAIL_LENGTH = 254
 const MAX_NAME_LENGTH = 255
 
-export const UserSchema = new Schema(
+const UserSchema = new Schema(
   {
     email: { type: String, default: '', maxlength: MAX_EMAIL_LENGTH },
     emails: [
@@ -247,4 +247,5 @@ function formatSplitTestsSchema(next) {
 }
 UserSchema.pre('save', formatSplitTestsSchema)
 
-export const User = mongoose.model('User', UserSchema)
+exports.User = mongoose.model('User', UserSchema)
+exports.UserSchema = UserSchema
diff --git a/services/web/app/src/models/UserAuditLogEntry.mjs b/services/web/app/src/models/UserAuditLogEntry.js
similarity index 70%
rename from services/web/app/src/models/UserAuditLogEntry.mjs
rename to services/web/app/src/models/UserAuditLogEntry.js
index 11442a9d0c..f239adca2f 100644
--- a/services/web/app/src/models/UserAuditLogEntry.mjs
+++ b/services/web/app/src/models/UserAuditLogEntry.js
@@ -1,7 +1,7 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
-export const UserAuditLogEntrySchema = new Schema(
+const UserAuditLogEntrySchema = new Schema(
   {
     userId: { type: Schema.Types.ObjectId, index: true },
     managedSubscriptionId: { type: Schema.Types.ObjectId, index: true },
@@ -17,7 +17,8 @@ export const UserAuditLogEntrySchema = new Schema(
   }
 )
 
-export const UserAuditLogEntry = mongoose.model(
+exports.UserAuditLogEntry = mongoose.model(
   'UserAuditLogEntry',
   UserAuditLogEntrySchema
 )
+exports.UserAuditLogEntrySchema = UserAuditLogEntrySchema
diff --git a/services/web/app/src/models/UserFeatureUsage.mjs b/services/web/app/src/models/UserFeatureUsage.js
similarity index 54%
rename from services/web/app/src/models/UserFeatureUsage.mjs
rename to services/web/app/src/models/UserFeatureUsage.js
index 50c86127af..8935990e0a 100644
--- a/services/web/app/src/models/UserFeatureUsage.mjs
+++ b/services/web/app/src/models/UserFeatureUsage.js
@@ -1,4 +1,4 @@
-import mongoose from '../infrastructure/Mongoose.js'
+const mongoose = require('../infrastructure/Mongoose')
 const { Schema } = mongoose
 
 const Usage = new Schema({
@@ -6,14 +6,16 @@ const Usage = new Schema({
   periodStart: { type: Date },
 })
 
-export const UserFeatureUsageSchema = new Schema({
+const UserFeatureUsageSchema = new Schema({
   features: {
     aiErrorAssistant: Usage,
     aiWorkbench: Usage,
   },
 })
 
-export const UserFeatureUsage = mongoose.model(
+exports.UserFeatureUsage = mongoose.model(
   'UserFeatureUsage',
   UserFeatureUsageSchema
 )
+
+exports.UserFeatureUsageSchema = UserFeatureUsageSchema
diff --git a/services/web/modules/launchpad/app/src/LaunchpadController.mjs b/services/web/modules/launchpad/app/src/LaunchpadController.mjs
index 94cc8b35a2..101372b3ca 100644
--- a/services/web/modules/launchpad/app/src/LaunchpadController.mjs
+++ b/services/web/modules/launchpad/app/src/LaunchpadController.mjs
@@ -6,7 +6,7 @@ import logger from '@overleaf/logger'
 import UserRegistrationHandler from '../../../../app/src/Features/User/UserRegistrationHandler.mjs'
 import EmailHandler from '../../../../app/src/Features/Email/EmailHandler.mjs'
 import UserGetter from '../../../../app/src/Features/User/UserGetter.mjs'
-import { User } from '../../../../app/src/models/User.mjs'
+import { User } from '../../../../app/src/models/User.js'
 import AuthenticationManager from '../../../../app/src/Features/Authentication/AuthenticationManager.mjs'
 import AuthenticationController from '../../../../app/src/Features/Authentication/AuthenticationController.mjs'
 import SessionManager from '../../../../app/src/Features/Authentication/SessionManager.mjs'
diff --git a/services/web/modules/launchpad/test/unit/src/LaunchpadController.test.mjs b/services/web/modules/launchpad/test/unit/src/LaunchpadController.test.mjs
index a0d3ce5b88..80150aa705 100644
--- a/services/web/modules/launchpad/test/unit/src/LaunchpadController.test.mjs
+++ b/services/web/modules/launchpad/test/unit/src/LaunchpadController.test.mjs
@@ -52,7 +52,7 @@ describe('LaunchpadController', function () {
       }),
     }))
 
-    vi.doMock('../../../../../app/src/models/User.mjs', () => ({
+    vi.doMock('../../../../../app/src/models/User.js', () => ({
       User: ctx.User,
     }))
 
diff --git a/services/web/modules/server-ce-scripts/scripts/export-legacy-user-projects.mjs b/services/web/modules/server-ce-scripts/scripts/export-legacy-user-projects.mjs
index 1598309f71..d7fcbed45d 100644
--- a/services/web/modules/server-ce-scripts/scripts/export-legacy-user-projects.mjs
+++ b/services/web/modules/server-ce-scripts/scripts/export-legacy-user-projects.mjs
@@ -11,8 +11,8 @@ import mongodb from '../../../app/src/infrastructure/mongodb.js'
 import DocumentUpdaterHandler from '../../../app/src/Features/DocumentUpdater/DocumentUpdaterHandler.js'
 import ProjectZipStreamManager from '../../../app/src/Features/Downloads/ProjectZipStreamManager.js'
 import logger from 'logger-sharelatex'
-import { Project } from '../../../app/src/models/Project.mjs'
-import { User } from '../../../app/src/models/User.mjs'
+import { Project } from '../../../app/src/models/Project.js'
+import { User } from '../../../app/src/models/User.js'
 import readline from 'readline'
 
 function parseArgs() {
diff --git a/services/web/modules/server-ce-scripts/scripts/export-user-projects.mjs b/services/web/modules/server-ce-scripts/scripts/export-user-projects.mjs
index f33edcddb8..c84e72037a 100644
--- a/services/web/modules/server-ce-scripts/scripts/export-user-projects.mjs
+++ b/services/web/modules/server-ce-scripts/scripts/export-user-projects.mjs
@@ -12,8 +12,8 @@ import ProjectZipStreamManager from '../../../app/src/Features/Downloads/Project
 import logger from '@overleaf/logger'
 import { promisify } from '@overleaf/promise-utils'
 import { gracefulShutdown } from '../../../app/src/infrastructure/GracefulShutdown.js'
-import { Project } from '../../../app/src/models/Project.mjs'
-import { User } from '../../../app/src/models/User.mjs'
+import { Project } from '../../../app/src/models/Project.js'
+import { User } from '../../../app/src/models/User.js'
 import readline from 'readline'
 
 function parseArgs() {
diff --git a/services/web/modules/server-ce-scripts/scripts/migrate-user-emails.mjs b/services/web/modules/server-ce-scripts/scripts/migrate-user-emails.mjs
index a5661c8978..b8cc54626b 100644
--- a/services/web/modules/server-ce-scripts/scripts/migrate-user-emails.mjs
+++ b/services/web/modules/server-ce-scripts/scripts/migrate-user-emails.mjs
@@ -14,12 +14,11 @@ import minimist from 'minimist'
 import os from 'os'
 import fs from 'fs'
 import * as csv from 'csv/sync'
-import EmailHelper from '../../../app/src/Features/Helpers/EmailHelper.mjs'
+import { parseEmail } from '../../../app/src/Features/Helpers/EmailHelper.js'
 import UserGetter from '../../../app/src/Features/User/UserGetter.mjs'
 import UserUpdater from '../../../app/src/Features/User/UserUpdater.mjs'
 import UserSessionsManager from '../../../app/src/Features/User/UserSessionsManager.mjs'
 
-const { parseEmail } = EmailHelper
 const hostname = os.hostname()
 const scriptTimestamp = new Date().toISOString()
 
diff --git a/services/web/modules/server-ce-scripts/scripts/transfer-all-projects-to-user.mjs b/services/web/modules/server-ce-scripts/scripts/transfer-all-projects-to-user.mjs
index 6c54e9a3b2..eafd301c0b 100644
--- a/services/web/modules/server-ce-scripts/scripts/transfer-all-projects-to-user.mjs
+++ b/services/web/modules/server-ce-scripts/scripts/transfer-all-projects-to-user.mjs
@@ -2,7 +2,7 @@ import { ObjectId } from '../../../app/src/infrastructure/mongodb.js'
 import minimist from 'minimist'
 import OwnershipTransferHandler from '../../../app/src/Features/Collaborators/OwnershipTransferHandler.mjs'
 import UserGetter from '../../../app/src/Features/User/UserGetter.mjs'
-import EmailHelper from '../../../app/src/Features/Helpers/EmailHelper.mjs'
+import EmailHelper from '../../../app/src/Features/Helpers/EmailHelper.js'
 
 const args = minimist(process.argv.slice(2), {
   string: ['from-user', 'to-user'],
diff --git a/services/web/scripts/add_salesforce_data_to_subscriptions.mjs b/services/web/scripts/add_salesforce_data_to_subscriptions.mjs
index 80cc4db36c..264640f587 100755
--- a/services/web/scripts/add_salesforce_data_to_subscriptions.mjs
+++ b/services/web/scripts/add_salesforce_data_to_subscriptions.mjs
@@ -3,7 +3,7 @@ import minimist from 'minimist'
 import { parse } from 'csv'
 import Stream from 'node:stream/promises'
 import { ObjectId } from '../app/src/infrastructure/mongodb.js'
-import { Subscription } from '../app/src/models/Subscription.mjs'
+import { Subscription } from '../app/src/models/Subscription.js'
 import { scriptRunner } from './lib/ScriptRunner.mjs'
 
 function usage() {
diff --git a/services/web/scripts/add_subscription_members_csv.mjs b/services/web/scripts/add_subscription_members_csv.mjs
index 25a29bed0d..1dbd5d8084 100644
--- a/services/web/scripts/add_subscription_members_csv.mjs
+++ b/services/web/scripts/add_subscription_members_csv.mjs
@@ -3,7 +3,7 @@ import minimist from 'minimist'
 import { parse } from 'csv'
 import Stream from 'node:stream/promises'
 import SubscriptionGroupHandler from '../app/src/Features/Subscription/SubscriptionGroupHandler.mjs'
-import { Subscription } from '../app/src/models/Subscription.mjs'
+import { Subscription } from '../app/src/models/Subscription.js'
 import { InvalidEmailError } from '../app/src/Features/Errors/Errors.js'
 
 function usage() {
diff --git a/services/web/scripts/analytics/sync_group_subscription_memberships.mjs b/services/web/scripts/analytics/sync_group_subscription_memberships.mjs
index 9480f7c32e..21ab920c5e 100644
--- a/services/web/scripts/analytics/sync_group_subscription_memberships.mjs
+++ b/services/web/scripts/analytics/sync_group_subscription_memberships.mjs
@@ -1,7 +1,7 @@
 import GoogleBigQueryHelper from './helpers/GoogleBigQueryHelper.mjs'
-import { Subscription } from '../../app/src/models/Subscription.mjs'
+import { Subscription } from '../../app/src/models/Subscription.js'
 import AnalyticsManager from '../../app/src/Features/Analytics/AnalyticsManager.mjs'
-import { DeletedSubscription } from '../../app/src/models/DeletedSubscription.mjs'
+import { DeletedSubscription } from '../../app/src/models/DeletedSubscription.js'
 import minimist from 'minimist'
 import _ from 'lodash'
 import mongodb from 'mongodb-legacy'
diff --git a/services/web/scripts/backfill_mixpanel_user_properties.mjs b/services/web/scripts/backfill_mixpanel_user_properties.mjs
index 6e3dabd4c2..1324cefb1d 100644
--- a/services/web/scripts/backfill_mixpanel_user_properties.mjs
+++ b/services/web/scripts/backfill_mixpanel_user_properties.mjs
@@ -1,5 +1,5 @@
 // @ts-check
-import '../app/src/models/User.mjs'
+import '../app/src/models/User.js'
 import { batchedUpdateWithResultHandling } from '@overleaf/mongo-utils/batchedUpdate.js'
 import { promiseMapWithLimit } from '@overleaf/promise-utils'
 import { getQueue } from '../app/src/infrastructure/Queues.js'
diff --git a/services/web/scripts/create_project.mjs b/services/web/scripts/create_project.mjs
index f883c00d5a..70f6ae4706 100644
--- a/services/web/scripts/create_project.mjs
+++ b/services/web/scripts/create_project.mjs
@@ -8,7 +8,7 @@ import path from 'node:path'
 import _ from 'lodash'
 import parseArgs from 'minimist'
 import OError from '@overleaf/o-error'
-import { User } from '../app/src/models/User.mjs'
+import { User } from '../app/src/models/User.js'
 import ProjectCreationHandler from '../app/src/Features/Project/ProjectCreationHandler.mjs'
 import ProjectEntityUpdateHandler from '../app/src/Features/Project/ProjectEntityUpdateHandler.mjs'
 import ProjectEntityHandler from '../app/src/Features/Project/ProjectEntityHandler.mjs'
diff --git a/services/web/scripts/delete_dangling_file_refs.mjs b/services/web/scripts/delete_dangling_file_refs.mjs
index 2a290b162c..df2ae91e22 100644
--- a/services/web/scripts/delete_dangling_file_refs.mjs
+++ b/services/web/scripts/delete_dangling_file_refs.mjs
@@ -8,7 +8,7 @@ import mongodb from 'mongodb-legacy'
 import { db } from '../app/src/infrastructure/mongodb.js'
 import Errors from '../app/src/Features/Errors/Errors.js'
 import ProjectEntityMongoUpdateHandler from '../app/src/Features/Project/ProjectEntityMongoUpdateHandler.mjs'
-import { iterablePaths } from '../app/src/Features/Project/IterablePath.mjs'
+import { iterablePaths } from '../app/src/Features/Project/IterablePath.js'
 import { scriptRunner } from './lib/ScriptRunner.mjs'
 import HistoryManager from '../app/src/Features/History/HistoryManager.mjs'
 
diff --git a/services/web/scripts/delete_subscriptions.mjs b/services/web/scripts/delete_subscriptions.mjs
index 6fb4610614..2cf17d75c2 100644
--- a/services/web/scripts/delete_subscriptions.mjs
+++ b/services/web/scripts/delete_subscriptions.mjs
@@ -1,4 +1,4 @@
-import { Subscription } from '../app/src/models/Subscription.mjs'
+import { Subscription } from '../app/src/models/Subscription.js'
 import SubscriptionUpdater from '../app/src/Features/Subscription/SubscriptionUpdater.mjs'
 import minimist from 'minimist'
 import mongodb from 'mongodb-legacy'
diff --git a/services/web/scripts/ensure_affiliations.mjs b/services/web/scripts/ensure_affiliations.mjs
index 72d19d8c31..5ffc0695ee 100644
--- a/services/web/scripts/ensure_affiliations.mjs
+++ b/services/web/scripts/ensure_affiliations.mjs
@@ -1,4 +1,4 @@
-import { User } from '../app/src/models/User.mjs'
+import { User } from '../app/src/models/User.js'
 import UserController from '../app/src/Features/User/UserController.mjs'
 import Logger from '@overleaf/logger'
 import pLimit from 'p-limit'
diff --git a/services/web/scripts/example/script_for_migration.mjs b/services/web/scripts/example/script_for_migration.mjs
index 2c73dc77d3..0c201eebab 100644
--- a/services/web/scripts/example/script_for_migration.mjs
+++ b/services/web/scripts/example/script_for_migration.mjs
@@ -6,7 +6,7 @@
  * in the migrations directory.
  */
 
-import { User } from '../../app/src/models/User.mjs'
+import { User } from '../../app/src/models/User.js'
 import { fileURLToPath } from 'node:url'
 
 // const somePackage = require('some-package')
diff --git a/services/web/scripts/extract_day1_churn_users.mjs b/services/web/scripts/extract_day1_churn_users.mjs
index d95cdf3959..0dd50e2099 100644
--- a/services/web/scripts/extract_day1_churn_users.mjs
+++ b/services/web/scripts/extract_day1_churn_users.mjs
@@ -2,7 +2,7 @@ import { scriptRunner } from './lib/ScriptRunner.mjs'
 import * as csv from 'csv'
 import fs from 'node:fs'
 import minimist from 'minimist'
-import { User } from '../app/src/models/User.mjs'
+import { User } from '../app/src/models/User.js'
 
 /**
  * This script extracts users who churned after day 1 - ie. their last session was within 24 hours of registering
diff --git a/services/web/scripts/extract_onboardingdatacollection_csv.mjs b/services/web/scripts/extract_onboardingdatacollection_csv.mjs
index 2eac33c3f7..a485a623dd 100644
--- a/services/web/scripts/extract_onboardingdatacollection_csv.mjs
+++ b/services/web/scripts/extract_onboardingdatacollection_csv.mjs
@@ -1,7 +1,7 @@
 import { scriptRunner } from './lib/ScriptRunner.mjs'
 import * as csv from 'csv'
 import fs from 'node:fs'
-import { OnboardingDataCollection } from '../app/src/models/OnboardingDataCollection.mjs'
+import { OnboardingDataCollection } from '../app/src/models/OnboardingDataCollection.js'
 
 /**
  * This script extracts the OnboardingDataCollection collection from the database
diff --git a/services/web/scripts/extract_onboardingdatacollection_never_used_latex.mjs b/services/web/scripts/extract_onboardingdatacollection_never_used_latex.mjs
index 57705c0aa5..339b08876e 100644
--- a/services/web/scripts/extract_onboardingdatacollection_never_used_latex.mjs
+++ b/services/web/scripts/extract_onboardingdatacollection_never_used_latex.mjs
@@ -2,8 +2,8 @@ import { scriptRunner } from './lib/ScriptRunner.mjs'
 import * as csv from 'csv'
 import fs from 'node:fs'
 import minimist from 'minimist'
-import { OnboardingDataCollection } from '../app/src/models/OnboardingDataCollection.mjs'
-import { User } from '../app/src/models/User.mjs'
+import { OnboardingDataCollection } from '../app/src/models/OnboardingDataCollection.js'
+import { User } from '../app/src/models/User.js'
 import SubscriptionLocator from '../app/src/Features/Subscription/SubscriptionLocator.mjs'
 import Settings from '@overleaf/settings'
 import { fetchJson } from '@overleaf/fetch-utils'
diff --git a/services/web/scripts/investigate_esm.mjs b/services/web/scripts/investigate_esm.mjs
deleted file mode 100644
index 9f31240e91..0000000000
--- a/services/web/scripts/investigate_esm.mjs
+++ /dev/null
@@ -1,147 +0,0 @@
-/* eslint-disable */
-import { extractImports, findJSAndImports } from './esm-check-migration.mjs'
-import path from 'node:path'
-import fs from 'node:fs'
-
-const imports = await findJSAndImports(
-  ['app', 'modules'].map(dir => path.resolve(dir))
-)
-
-const entryPoint = fs.existsSync('app.js') ? 'app.js' : 'app.mjs'
-imports.set(path.resolve(entryPoint), extractImports(entryPoint))
-
-const moduleImports = new Map()
-imports.forEach((deps, module) => {
-  for (const dep of deps) {
-    if (!moduleImports.has(dep)) {
-      moduleImports.set(dep, new Set())
-    }
-    moduleImports.set(dep, moduleImports.get(dep).add(module))
-  }
-})
-
-const soloImports = new Map()
-moduleImports.forEach((importedBy, module) => {
-  if (importedBy.size === 1) {
-    soloImports.set(module, [...importedBy][0])
-  }
-})
-
-console.log(soloImports)
-
-for (const [module, importedBy] of soloImports) {
-  if (!moduleImports.has(importedBy)) {
-    console.log(
-      `${module} is only imported by ${importedBy}, which has no other imports`
-    )
-  }
-  if (soloImports.has(importedBy)) {
-    console.log(
-      `${module} is only imported by ${importedBy}, which is only imported by ${soloImports.get(importedBy)}`
-    )
-  }
-  const chains = findDependencyChainsToTarget(imports, module)
-  const conversionsToMake = chains.reduce((conversions, chain) => {
-    chain.forEach(dep => {
-      conversions.add(dep)
-    })
-    return conversions
-  }, new Set())
-
-  if (conversionsToMake.length < 10) {
-    console.log(
-      `To convert ${module}, would need to convert: ${[...conversionsToMake].length}`
-    )
-  }
-}
-
-// --- Circular dependency detection ---
-function findCircularDependencies(importsMap) {
-  const cycles = []
-  const visited = new Set()
-  const stack = []
-
-  function dfs(file, pathStack) {
-    if (pathStack.includes(file)) {
-      // Cycle detected
-      const cycleStart = pathStack.indexOf(file)
-      cycles.push(pathStack.slice(cycleStart).concat(file))
-      return
-    }
-    if (!importsMap.has(file)) return
-    pathStack.push(file)
-    for (const imp of importsMap.get(file)) {
-      const resolvedImp = path.resolve(imp)
-      dfs(resolvedImp, pathStack)
-    }
-    pathStack.pop()
-  }
-
-  for (const file of importsMap.keys()) {
-    dfs(file, [])
-  }
-  return cycles
-}
-
-const cycles = findCircularDependencies(imports)
-if (cycles.length > 0) {
-  console.log('Circular dependencies found:')
-  for (const cycle of cycles) {
-    console.log('  ' + cycle.join(' -> '))
-  }
-} else {
-  console.log('No circular dependencies detected.')
-}
-
-// --- Find all chains of dependencies to a target file ---
-function findDependencyChainsToTarget(importsMap, targetPath) {
-  const chains = []
-  const resolvedTarget = path.resolve(targetPath)
-
-  function dfs(current, pathStack) {
-    if (pathStack.includes(current)) return // avoid cycles
-    pathStack.push(current)
-    if (current === resolvedTarget) {
-      chains.push([...pathStack])
-      pathStack.pop()
-      return
-    }
-    if (!importsMap.has(current)) {
-      pathStack.pop()
-      return
-    }
-    for (const imp of importsMap.get(current)) {
-      const resolvedImp = path.resolve(imp)
-      dfs(resolvedImp, pathStack)
-    }
-    pathStack.pop()
-  }
-
-  for (const file of importsMap.keys()) {
-    if (file === resolvedTarget) continue // skip self
-    dfs(file, [])
-  }
-  return chains
-}
-
-// Example usage: set your target file path here
-const targetFile =
-  '/Users/arumble/Documents/Projects/internal/services/web/app/src/Features/Analytics/AnalyticsManager.js' // <-- change to your target
-const chains = findDependencyChainsToTarget(imports, targetFile)
-if (chains.length > 0) {
-  console.log(`Dependency chains leading to ${targetFile}:`)
-  for (const chain of chains) {
-    console.log('  ' + chain.join(' -> '))
-  }
-} else {
-  console.log(`No dependency chains found leading to ${targetFile}.`)
-}
-
-const conversionsToMake = chains.reduce((conversions, chain) => {
-  chain.forEach(dep => {
-    conversions.add(dep)
-  })
-  return conversions
-}, new Set())
-
-console.log([...conversionsToMake].join(' '))
diff --git a/services/web/scripts/re_add_deleted_emails.mjs b/services/web/scripts/re_add_deleted_emails.mjs
index 8d8a620505..e910073c5a 100644
--- a/services/web/scripts/re_add_deleted_emails.mjs
+++ b/services/web/scripts/re_add_deleted_emails.mjs
@@ -10,7 +10,7 @@ import Errors from '../app/src/Features/Errors/Errors.js'
 import UserGetter from '../app/src/Features/User/UserGetter.mjs'
 import { READ_PREFERENCE_SECONDARY } from '@overleaf/mongo-utils/batchedUpdate.js'
 import UserUpdater from '../app/src/Features/User/UserUpdater.mjs'
-import EmailHelper from '../app/src/Features/Helpers/EmailHelper.mjs'
+import EmailHelper from '../app/src/Features/Helpers/EmailHelper.js'
 import AsyncLocalStorage from '../app/src/infrastructure/AsyncLocalStorage.js'
 import AnalyticsManager from '../app/src/Features/Analytics/AnalyticsManager.mjs'
 import UserAuditLogHandler from '../app/src/Features/User/UserAuditLogHandler.mjs'
diff --git a/services/web/scripts/recurly/resync_recurly_state_single_subscription.mjs b/services/web/scripts/recurly/resync_recurly_state_single_subscription.mjs
index f72809a965..13b005b02a 100644
--- a/services/web/scripts/recurly/resync_recurly_state_single_subscription.mjs
+++ b/services/web/scripts/recurly/resync_recurly_state_single_subscription.mjs
@@ -1,4 +1,4 @@
-import { Subscription } from '../../app/src/models/Subscription.mjs'
+import { Subscription } from '../../app/src/models/Subscription.js'
 import RecurlyWrapper from '../../app/src/Features/Subscription/RecurlyWrapper.mjs'
 import SubscriptionUpdater from '../../app/src/Features/Subscription/SubscriptionUpdater.mjs'
 import minimist from 'minimist'
diff --git a/services/web/scripts/recurly/resync_subscriptions.mjs b/services/web/scripts/recurly/resync_subscriptions.mjs
index 17b4bfa9db..00f10b7b29 100644
--- a/services/web/scripts/recurly/resync_subscriptions.mjs
+++ b/services/web/scripts/recurly/resync_subscriptions.mjs
@@ -1,4 +1,4 @@
-import { Subscription } from '../../app/src/models/Subscription.mjs'
+import { Subscription } from '../../app/src/models/Subscription.js'
 import RecurlyWrapper from '../../app/src/Features/Subscription/RecurlyWrapper.mjs'
 import SubscriptionUpdater from '../../app/src/Features/Subscription/SubscriptionUpdater.mjs'
 import minimist from 'minimist'
diff --git a/services/web/scripts/remove_oauth_application.mjs b/services/web/scripts/remove_oauth_application.mjs
index 95eddfca94..fd37ca374c 100644
--- a/services/web/scripts/remove_oauth_application.mjs
+++ b/services/web/scripts/remove_oauth_application.mjs
@@ -1,4 +1,4 @@
-import { OauthApplication } from '../app/src/models/OauthApplication.mjs'
+import { OauthApplication } from '../app/src/models/OauthApplication.js'
 import parseArgs from 'minimist'
 import OError from '@overleaf/o-error'
 import { scriptRunner } from './lib/ScriptRunner.mjs'
diff --git a/services/web/scripts/remove_user_enrollment.mjs b/services/web/scripts/remove_user_enrollment.mjs
index 64073607a9..a4ebcdb4d2 100644
--- a/services/web/scripts/remove_user_enrollment.mjs
+++ b/services/web/scripts/remove_user_enrollment.mjs
@@ -7,8 +7,8 @@
 
 import minimist from 'minimist'
 import { ObjectId } from '../app/src/infrastructure/mongodb.js'
-import { User } from '../app/src/models/User.mjs'
-import { Subscription } from '../app/src/models/Subscription.mjs'
+import { User } from '../app/src/models/User.js'
+import { Subscription } from '../app/src/models/Subscription.js'
 import UserAuditLogHandler from '../app/src/Features/User/UserAuditLogHandler.mjs'
 
 const argv = minimist(process.argv.slice(2))
diff --git a/services/web/scripts/set_tex_live_image.mjs b/services/web/scripts/set_tex_live_image.mjs
index f513afe0bc..a0d48dd9f3 100644
--- a/services/web/scripts/set_tex_live_image.mjs
+++ b/services/web/scripts/set_tex_live_image.mjs
@@ -1,6 +1,6 @@
 import Settings from '@overleaf/settings'
 import mongodb from 'mongodb-legacy'
-import { Project } from '../app/src/models/Project.mjs'
+import { Project } from '../app/src/models/Project.js'
 import { scriptRunner } from './lib/ScriptRunner.mjs'
 
 const { ObjectId } = mongodb
diff --git a/services/web/scripts/validate-data-of-model.mjs b/services/web/scripts/validate-data-of-model.mjs
index 63788bef6d..7c9aa38f0c 100644
--- a/services/web/scripts/validate-data-of-model.mjs
+++ b/services/web/scripts/validate-data-of-model.mjs
@@ -3,8 +3,9 @@ import { db } from '../app/src/infrastructure/mongodb.js'
 
 const MODEL_NAME = process.argv.pop()
 
+// Todo: handle mjs file once models have been converted to ES module
 const { [MODEL_NAME]: Model } = await import(
-  `../app/src/models/${MODEL_NAME}.mjs`
+  `../app/src/models/${MODEL_NAME}.js`
 )
 
 function processBatch(batch) {
diff --git a/services/web/test/acceptance/src/ConvertEmailConfirmedAtToDates.mjs b/services/web/test/acceptance/src/ConvertEmailConfirmedAtToDates.js
similarity index 100%
rename from services/web/test/acceptance/src/ConvertEmailConfirmedAtToDates.mjs
rename to services/web/test/acceptance/src/ConvertEmailConfirmedAtToDates.js
diff --git a/services/web/test/acceptance/src/ConvertSplitTestAssignedAtToDates.mjs b/services/web/test/acceptance/src/ConvertSplitTestAssignedAtToDates.js
similarity index 100%
rename from services/web/test/acceptance/src/ConvertSplitTestAssignedAtToDates.mjs
rename to services/web/test/acceptance/src/ConvertSplitTestAssignedAtToDates.js
diff --git a/services/web/test/acceptance/src/ModelTests.mjs b/services/web/test/acceptance/src/ModelTests.mjs
index 9ef32cf08c..7a58cf0a53 100644
--- a/services/web/test/acceptance/src/ModelTests.mjs
+++ b/services/web/test/acceptance/src/ModelTests.mjs
@@ -1,6 +1,6 @@
 import { expect } from 'chai'
-import { User } from '../../../app/src/models/User.mjs'
-import { Subscription } from '../../../app/src/models/Subscription.mjs'
+import { User } from '../../../app/src/models/User.js'
+import { Subscription } from '../../../app/src/models/Subscription.js'
 
 describe('mongoose', function () {
   describe('User', function () {
diff --git a/services/web/test/acceptance/src/MongoHelper.mjs b/services/web/test/acceptance/src/MongoHelper.mjs
index dc7ddbeab6..269939e8ff 100644
--- a/services/web/test/acceptance/src/MongoHelper.mjs
+++ b/services/web/test/acceptance/src/MongoHelper.mjs
@@ -1,7 +1,7 @@
 import { expect } from 'chai'
 import mongodb from 'mongodb-legacy'
 import mongoose from 'mongoose'
-import { User as UserModel } from '../../../app/src/models/User.mjs'
+import { User as UserModel } from '../../../app/src/models/User.js'
 import { db } from '../../../app/src/infrastructure/mongodb.js'
 import {
   normalizeQuery,
diff --git a/services/web/test/acceptance/src/ProjectCRUDTests.mjs b/services/web/test/acceptance/src/ProjectCRUDTests.mjs
index 2c6d638e9f..71bad436d0 100644
--- a/services/web/test/acceptance/src/ProjectCRUDTests.mjs
+++ b/services/web/test/acceptance/src/ProjectCRUDTests.mjs
@@ -1,9 +1,9 @@
 import { expect } from 'chai'
 import UserHelper from './helpers/User.mjs'
-import { Project } from '../../../app/src/models/Project.mjs'
+import { Project } from '../../../app/src/models/Project.js'
 import mongodb from 'mongodb-legacy'
 import cheerio from 'cheerio'
-import { Subscription } from '../../../app/src/models/Subscription.mjs'
+import { Subscription } from '../../../app/src/models/Subscription.js'
 import Features from '../../../app/src/infrastructure/Features.js'
 
 const ObjectId = mongodb.ObjectId
diff --git a/services/web/test/acceptance/src/ProjectStructureTests.mjs b/services/web/test/acceptance/src/ProjectStructureTests.mjs
index 22e22a9fcc..14edf58c4f 100644
--- a/services/web/test/acceptance/src/ProjectStructureTests.mjs
+++ b/services/web/test/acceptance/src/ProjectStructureTests.mjs
@@ -2,7 +2,7 @@ import chai, { expect } from 'chai'
 import mongodb from 'mongodb-legacy'
 import Path from 'node:path'
 import fs from 'node:fs'
-import { Project } from '../../../app/src/models/Project.mjs'
+import { Project } from '../../../app/src/models/Project.js'
 import ProjectGetter from '../../../app/src/Features/Project/ProjectGetter.mjs'
 import UserHelper from './helpers/User.mjs'
 import MockDocStoreApiClass from './mocks/MockDocstoreApi.mjs'
diff --git a/services/web/test/acceptance/src/helpers/DeletedSubscription.mjs b/services/web/test/acceptance/src/helpers/DeletedSubscription.mjs
index 2e218c6f26..3d64877cec 100644
--- a/services/web/test/acceptance/src/helpers/DeletedSubscription.mjs
+++ b/services/web/test/acceptance/src/helpers/DeletedSubscription.mjs
@@ -1,8 +1,8 @@
 import { expect } from 'chai'
 import MockSubscription from './Subscription.mjs'
 import SubscriptionUpdater from '../../../../app/src/Features/Subscription/SubscriptionUpdater.mjs'
-import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.mjs'
-import { DeletedSubscription as DeletedSubscriptionModel } from '../../../../app/src/models/DeletedSubscription.mjs'
+import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.js'
+import { DeletedSubscription as DeletedSubscriptionModel } from '../../../../app/src/models/DeletedSubscription.js'
 import { promisifyClass } from '@overleaf/promise-utils'
 
 class DeletedSubscription {
diff --git a/services/web/test/acceptance/src/helpers/Institution.mjs b/services/web/test/acceptance/src/helpers/Institution.mjs
index 416c61bc99..eb2bd0b274 100644
--- a/services/web/test/acceptance/src/helpers/Institution.mjs
+++ b/services/web/test/acceptance/src/helpers/Institution.mjs
@@ -1,5 +1,5 @@
 import mongodb from 'mongodb-legacy'
-import { Institution as InstitutionModel } from '../../../../app/src/models/Institution.mjs'
+import { Institution as InstitutionModel } from '../../../../app/src/models/Institution.js'
 
 const { ObjectId } = mongodb
 
diff --git a/services/web/test/acceptance/src/helpers/Publisher.mjs b/services/web/test/acceptance/src/helpers/Publisher.mjs
index 8d8e336332..8300157cc2 100644
--- a/services/web/test/acceptance/src/helpers/Publisher.mjs
+++ b/services/web/test/acceptance/src/helpers/Publisher.mjs
@@ -1,5 +1,5 @@
 import mongodb from 'mongodb-legacy'
-import { Publisher as PublisherModel } from '../../../../app/src/models/Publisher.mjs'
+import { Publisher as PublisherModel } from '../../../../app/src/models/Publisher.js'
 import { callbackifyClass } from '@overleaf/promise-utils'
 
 const { ObjectId } = mongodb
diff --git a/services/web/test/acceptance/src/helpers/SAMLHelper.mjs b/services/web/test/acceptance/src/helpers/SAMLHelper.mjs
index d4092eb6f3..531e3fdacc 100644
--- a/services/web/test/acceptance/src/helpers/SAMLHelper.mjs
+++ b/services/web/test/acceptance/src/helpers/SAMLHelper.mjs
@@ -1,7 +1,7 @@
 import fs from 'node:fs'
 import path from 'node:path'
 import { SignedXml } from 'xml-crypto'
-import { SamlLog } from '../../../../app/src/models/SamlLog.mjs'
+import { SamlLog } from '../../../../app/src/models/SamlLog.js'
 import { expect } from 'chai'
 import zlib from 'node:zlib'
 import { fileURLToPath } from 'node:url'
diff --git a/services/web/test/acceptance/src/helpers/Subscription.mjs b/services/web/test/acceptance/src/helpers/Subscription.mjs
index afa1297de0..eec39c3bf6 100644
--- a/services/web/test/acceptance/src/helpers/Subscription.mjs
+++ b/services/web/test/acceptance/src/helpers/Subscription.mjs
@@ -4,8 +4,8 @@ import { callbackifyClass } from '@overleaf/promise-utils'
 import SubscriptionUpdater from '../../../../app/src/Features/Subscription/SubscriptionUpdater.mjs'
 import PermissionsManager from '../../../../app/src/Features/Authorization/PermissionsManager.mjs'
 import SSOConfigManager from '../../../../modules/group-settings/app/src/sso/SSOConfigManager.mjs'
-import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.mjs'
-import { DeletedSubscription as DeletedSubscriptionModel } from '../../../../app/src/models/DeletedSubscription.mjs'
+import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.js'
+import { DeletedSubscription as DeletedSubscriptionModel } from '../../../../app/src/models/DeletedSubscription.js'
 import Modules from '../../../../app/src/infrastructure/Modules.js'
 
 class PromisifiedSubscription {
diff --git a/services/web/test/acceptance/src/helpers/User.mjs b/services/web/test/acceptance/src/helpers/User.mjs
index 3bc4d801f1..48ba98c9b5 100644
--- a/services/web/test/acceptance/src/helpers/User.mjs
+++ b/services/web/test/acceptance/src/helpers/User.mjs
@@ -2,14 +2,16 @@ import OError from '@overleaf/o-error'
 import request from './request.js'
 import settings from '@overleaf/settings'
 import { db, ObjectId } from '../../../../app/src/infrastructure/mongodb.js'
-import { User as UserModel } from '../../../../app/src/models/User.mjs'
+import { User as UserModel } from '../../../../app/src/models/User.js'
 import UserUpdater from '../../../../app/src/Features/User/UserUpdater.mjs'
 import AuthenticationManager from '../../../../app/src/Features/Authentication/AuthenticationManager.mjs'
 import { promisifyClass } from '@overleaf/promise-utils'
 import fs from 'node:fs'
 import Path from 'node:path'
+import { fileURLToPath } from 'node:url'
 import { Cookie } from 'tough-cookie'
 
+const __dirname = fileURLToPath(new URL('.', import.meta.url))
 const COOKIE_DOMAIN = settings.cookieDomain
 // The cookie domain has a leading '.' but the cookie jar stores it without.
 const DEFAULT_COOKIE_URL = `https://${COOKIE_DOMAIN.replace(/^\./, '')}/`
@@ -851,7 +853,7 @@ class User {
     callback
   ) {
     const fileStream = fs.createReadStream(
-      Path.resolve(Path.join(import.meta.dirname, '..', '..', 'files', file))
+      Path.resolve(Path.join(__dirname, '..', '..', 'files', file))
     )
 
     this.request.post(
diff --git a/services/web/test/acceptance/src/helpers/UserHelper.mjs b/services/web/test/acceptance/src/helpers/UserHelper.mjs
index aea5ca66ee..b218554da0 100644
--- a/services/web/test/acceptance/src/helpers/UserHelper.mjs
+++ b/services/web/test/acceptance/src/helpers/UserHelper.mjs
@@ -9,7 +9,7 @@ import moment from 'moment'
 import fetch from 'node-fetch'
 import mongodb from 'mongodb-legacy'
 
-import { UserAuditLogEntry } from '../../../../app/src/models/UserAuditLogEntry.mjs'
+import { UserAuditLogEntry } from '../../../../app/src/models/UserAuditLogEntry.js'
 
 // Import the rate limiter so we can clear it between tests
 
diff --git a/services/web/test/acceptance/src/helpers/groupSSO.mjs b/services/web/test/acceptance/src/helpers/groupSSO.mjs
index d72fd372e1..c908773ed6 100644
--- a/services/web/test/acceptance/src/helpers/groupSSO.mjs
+++ b/services/web/test/acceptance/src/helpers/groupSSO.mjs
@@ -2,14 +2,14 @@ import fs from 'node:fs'
 import Path from 'node:path'
 import UserModule from './User.mjs'
 import SubscriptionHelper from './Subscription.mjs'
-import { SSOConfig } from '../../../../app/src/models/SSOConfig.mjs'
+import { SSOConfig } from '../../../../app/src/models/SSOConfig.js'
 import UserHelper from './UserHelper.mjs'
 import SAMLHelper from './SAMLHelper.mjs'
 import Settings from '@overleaf/settings'
 import GroupUtils from '../../../../app/src/Features/Subscription/GroupUtils.mjs'
 import UserGetter from '../../../../app/src/Features/User/UserGetter.mjs'
 import { fileURLToPath } from 'node:url'
-import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.mjs'
+import { Subscription as SubscriptionModel } from '../../../../app/src/models/Subscription.js'
 
 const { promises: User } = UserModule
 const { promises: Subscription } = SubscriptionHelper
diff --git a/services/web/test/unit/src/Collaborators/CollaboratorsGetter.test.mjs b/services/web/test/unit/src/Collaborators/CollaboratorsGetter.test.mjs
index cd6506c7d4..02fd445098 100644
--- a/services/web/test/unit/src/Collaborators/CollaboratorsGetter.test.mjs
+++ b/services/web/test/unit/src/Collaborators/CollaboratorsGetter.test.mjs
@@ -2,9 +2,11 @@ import { vi, expect } from 'vitest'
 import Path from 'path'
 import sinon from 'sinon'
 import mongodb from 'mongodb-legacy'
-import { Project } from '../../../../app/src/models/Project.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
 
+const { Project } = indirectlyImportModels(['Project'])
+
 const { ObjectId } = mongodb
 
 vi.mock('../../../../app/src/Features/Errors/Errors.js', () =>
diff --git a/services/web/test/unit/src/Collaborators/CollaboratorsHandler.test.mjs b/services/web/test/unit/src/Collaborators/CollaboratorsHandler.test.mjs
index fa4e4bc2b2..f3f924125e 100644
--- a/services/web/test/unit/src/Collaborators/CollaboratorsHandler.test.mjs
+++ b/services/web/test/unit/src/Collaborators/CollaboratorsHandler.test.mjs
@@ -2,11 +2,12 @@ import { vi, expect } from 'vitest'
 import path from 'path'
 import sinon from 'sinon'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
-import { Project } from '../../../../app/src/models/Project.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
 import mongodb from 'mongodb-legacy'
 import { setTimeout } from 'node:timers/promises'
 
 const { ObjectId } = mongodb
+const { Project } = indirectlyImportModels(['Project'])
 vi.mock('../../../../app/src/Features/Errors/Errors.js', () =>
   vi.importActual('../../../../app/src/Features/Errors/Errors.js')
 )
diff --git a/services/web/test/unit/src/Collaborators/CollaboratorsInviteHandler.test.mjs b/services/web/test/unit/src/Collaborators/CollaboratorsInviteHandler.test.mjs
index 41e5e3eba5..660994f2f8 100644
--- a/services/web/test/unit/src/Collaborators/CollaboratorsInviteHandler.test.mjs
+++ b/services/web/test/unit/src/Collaborators/CollaboratorsInviteHandler.test.mjs
@@ -82,7 +82,7 @@ describe('CollaboratorsInviteHandler', function () {
       default: ctx.settings,
     }))
 
-    vi.doMock('../../../../app/src/models/ProjectInvite.mjs', () => ({
+    vi.doMock('../../../../app/src/models/ProjectInvite.js', () => ({
       ProjectInvite: ctx.ProjectInvite,
     }))
 
diff --git a/services/web/test/unit/src/Collaborators/OwnershipTransferHandler.test.mjs b/services/web/test/unit/src/Collaborators/OwnershipTransferHandler.test.mjs
index 35e48e2e15..f526aaa29b 100644
--- a/services/web/test/unit/src/Collaborators/OwnershipTransferHandler.test.mjs
+++ b/services/web/test/unit/src/Collaborators/OwnershipTransferHandler.test.mjs
@@ -89,7 +89,7 @@ describe('OwnershipTransferHandler', function () {
       default: ctx.ProjectGetter,
     }))
 
-    vi.doMock('../../../../app/src/models/Project.mjs', () => ({
+    vi.doMock('../../../../app/src/models/Project.js', () => ({
       Project: ctx.ProjectModel,
     }))
 
diff --git a/services/web/test/unit/src/Cooldown/CooldownManager.sequential.test.mjs b/services/web/test/unit/src/Cooldown/CooldownManagerTests.js
similarity index 53%
rename from services/web/test/unit/src/Cooldown/CooldownManager.sequential.test.mjs
rename to services/web/test/unit/src/Cooldown/CooldownManagerTests.js
index fdd757f03f..5531c4b8ea 100644
--- a/services/web/test/unit/src/Cooldown/CooldownManager.sequential.test.mjs
+++ b/services/web/test/unit/src/Cooldown/CooldownManagerTests.js
@@ -1,16 +1,16 @@
-import { expect } from 'vitest'
-import mongodb from 'mongodb-legacy'
-import CooldownManager from '../../../../app/src/Features/Cooldown/CooldownManager.mjs'
-import { cleanupTestRedis } from '../../../../app/src/infrastructure/RedisWrapper.js'
-
-const { ObjectId } = mongodb
+const { expect } = require('chai')
+const { ObjectId } = require('mongodb-legacy')
+const CooldownManager = require('../../../../app/src/Features/Cooldown/CooldownManager')
+const {
+  cleanupTestRedis,
+} = require('../../../../app/src/infrastructure/RedisWrapper')
 
 describe('CooldownManager', function () {
   beforeEach(cleanupTestRedis)
 
-  beforeEach(function (ctx) {
-    ctx.project1Id = new ObjectId().toString()
-    ctx.project2Id = new ObjectId().toString()
+  beforeEach(function () {
+    this.project1Id = new ObjectId().toString()
+    this.project2Id = new ObjectId().toString()
   })
 
   describe('_buildKey', function () {
@@ -21,35 +21,35 @@ describe('CooldownManager', function () {
 
   describe('isProjectOnCooldown', function () {
     describe('when no project is on cooldown', function () {
-      it('returns false for project 1', async function (ctx) {
+      it('returns false for project 1', async function () {
         const result = await CooldownManager.promises.isProjectOnCooldown(
-          ctx.project1Id
+          this.project1Id
         )
         expect(result).to.be.false
       })
 
-      it('returns false for project 2', async function (ctx) {
+      it('returns false for project 2', async function () {
         const result = await CooldownManager.promises.isProjectOnCooldown(
-          ctx.project2Id
+          this.project2Id
         )
         expect(result).to.be.false
       })
     })
     describe('when project 1 is on cooldown', function () {
-      beforeEach(async function (ctx) {
-        await CooldownManager.promises.putProjectOnCooldown(ctx.project1Id)
+      beforeEach(async function () {
+        await CooldownManager.promises.putProjectOnCooldown(this.project1Id)
       })
 
-      it('returns true for project 1', async function (ctx) {
+      it('returns true for project 1', async function () {
         const result = await CooldownManager.promises.isProjectOnCooldown(
-          ctx.project1Id
+          this.project1Id
         )
         expect(result).to.be.true
       })
 
-      it('returns false for project 2', async function (ctx) {
+      it('returns false for project 2', async function () {
         const result = await CooldownManager.promises.isProjectOnCooldown(
-          ctx.project2Id
+          this.project2Id
         )
         expect(result).to.be.false
       })
diff --git a/services/web/test/unit/src/Cooldown/CooldownMiddleware.test.mjs b/services/web/test/unit/src/Cooldown/CooldownMiddleware.test.mjs
index f7294c3b08..846a54d4ce 100644
--- a/services/web/test/unit/src/Cooldown/CooldownMiddleware.test.mjs
+++ b/services/web/test/unit/src/Cooldown/CooldownMiddleware.test.mjs
@@ -10,7 +10,7 @@ describe('CooldownMiddleware', function () {
     ctx.CooldownManager = { isProjectOnCooldown: sinon.stub() }
 
     vi.doMock(
-      '../../../../app/src/Features/Cooldown/CooldownManager.mjs',
+      '../../../../app/src/Features/Cooldown/CooldownManager.js',
       () => ({
         default: ctx.CooldownManager,
       })
diff --git a/services/web/test/unit/src/HelperFiles/DiffHelper.test.mjs b/services/web/test/unit/src/HelperFiles/DiffHelperTests.js
similarity index 87%
rename from services/web/test/unit/src/HelperFiles/DiffHelper.test.mjs
rename to services/web/test/unit/src/HelperFiles/DiffHelperTests.js
index b1149aa5b4..518bffc534 100644
--- a/services/web/test/unit/src/HelperFiles/DiffHelper.test.mjs
+++ b/services/web/test/unit/src/HelperFiles/DiffHelperTests.js
@@ -1,5 +1,7 @@
-import { expect } from 'vitest'
-import { stringSimilarity } from '../../../../app/src/Features/Helpers/DiffHelper.mjs'
+const { expect } = require('chai')
+const {
+  stringSimilarity,
+} = require('../../../../app/src/Features/Helpers/DiffHelper')
 
 describe('DiffHelper', function () {
   describe('stringSimilarity', function () {
diff --git a/services/web/test/unit/src/HelperFiles/EmailHelper.test.mjs b/services/web/test/unit/src/HelperFiles/EmailHelperTests.js
similarity index 53%
rename from services/web/test/unit/src/HelperFiles/EmailHelper.test.mjs
rename to services/web/test/unit/src/HelperFiles/EmailHelperTests.js
index 31660b284f..2d56b7c638 100644
--- a/services/web/test/unit/src/HelperFiles/EmailHelper.test.mjs
+++ b/services/web/test/unit/src/HelperFiles/EmailHelperTests.js
@@ -1,19 +1,21 @@
-import { expect } from 'vitest'
-import EmailHelper from '../../../../app/src/Features/Helpers/EmailHelper.mjs'
+const { expect } = require('chai')
+const {
+  parseEmail,
+} = require('../../../../app/src/Features/Helpers/EmailHelper')
 
 describe('EmailHelper', function () {
   it('should parse a single email', function () {
     const address = 'test@example.com'
     const expected = 'test@example.com'
-    expect(EmailHelper.parseEmail(address)).to.equal(expected)
-    expect(EmailHelper.parseEmail(address, true)).to.equal(expected)
+    expect(parseEmail(address)).to.equal(expected)
+    expect(parseEmail(address, true)).to.equal(expected)
   })
 
   it('should parse a valid email address', function () {
     const address = '"Test Person" <test@example.com>'
     const expected = 'test@example.com'
-    expect(EmailHelper.parseEmail(address)).to.equal(null)
-    expect(EmailHelper.parseEmail(address, true)).to.equal(expected)
+    expect(parseEmail(address)).to.equal(null)
+    expect(parseEmail(address, true)).to.equal(expected)
   })
 
   it('should return null for garbage input', function () {
@@ -29,26 +31,26 @@ describe('EmailHelper', function () {
       { toString: true },
     ]
     for (const input of cases) {
-      expect(EmailHelper.parseEmail(input)).to.equal(null, input)
-      expect(EmailHelper.parseEmail(input, true)).to.equal(null, input)
+      expect(parseEmail(input)).to.equal(null, input)
+      expect(parseEmail(input, true)).to.equal(null, input)
     }
   })
 
   it('should return null for an invalid single email', function () {
     const address = 'testexample.com'
-    expect(EmailHelper.parseEmail(address)).to.equal(null)
-    expect(EmailHelper.parseEmail(address, true)).to.equal(null)
+    expect(parseEmail(address)).to.equal(null)
+    expect(parseEmail(address, true)).to.equal(null)
   })
 
   it('should return null for an invalid email address', function () {
     const address = '"Test Person" test@example.com>'
-    expect(EmailHelper.parseEmail(address)).to.equal(null)
-    expect(EmailHelper.parseEmail(address, true)).to.equal(null)
+    expect(parseEmail(address)).to.equal(null)
+    expect(parseEmail(address, true)).to.equal(null)
   })
 
   it('should return null for a group of addresses', function () {
     const address = 'Group name:test1@example.com,test2@example.com;'
-    expect(EmailHelper.parseEmail(address)).to.equal(null)
-    expect(EmailHelper.parseEmail(address, true)).to.equal(null)
+    expect(parseEmail(address)).to.equal(null)
+    expect(parseEmail(address, true)).to.equal(null)
   })
 })
diff --git a/services/web/test/unit/src/Project/IterablePath.test.mjs b/services/web/test/unit/src/Project/IterablePathTests.js
similarity index 77%
rename from services/web/test/unit/src/Project/IterablePath.test.mjs
rename to services/web/test/unit/src/Project/IterablePathTests.js
index 88f6e3abc4..e00607eb69 100644
--- a/services/web/test/unit/src/Project/IterablePath.test.mjs
+++ b/services/web/test/unit/src/Project/IterablePathTests.js
@@ -1,5 +1,7 @@
-import { expect } from 'vitest'
-import { iterablePaths } from '../../../../app/src/Features/Project/IterablePath.mjs'
+const { expect } = require('chai')
+const {
+  iterablePaths,
+} = require('../../../../app/src/Features/Project/IterablePath')
 
 describe('iterablePaths', function () {
   it('returns an empty array for empty folders', function () {
diff --git a/services/web/test/unit/src/Project/ProjectCollabratecDetails.test.mjs b/services/web/test/unit/src/Project/ProjectCollabratecDetails.test.mjs
index 8907fdda2d..68ab92e3c5 100644
--- a/services/web/test/unit/src/Project/ProjectCollabratecDetails.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectCollabratecDetails.test.mjs
@@ -18,7 +18,7 @@ describe('ProjectCollabratecDetailsHandler', function () {
       default: { ObjectId },
     }))
 
-    vi.doMock('../../../../app/src/models/Project.mjs', () => ({
+    vi.doMock('../../../../app/src/models/Project.js', () => ({
       Project: ctx.ProjectModel,
     }))
 
diff --git a/services/web/test/unit/src/Project/ProjectDeleter.test.mjs b/services/web/test/unit/src/Project/ProjectDeleter.test.mjs
index 0b58751221..5dbea99d6c 100644
--- a/services/web/test/unit/src/Project/ProjectDeleter.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectDeleter.test.mjs
@@ -2,12 +2,15 @@ import { vi, expect } from 'vitest'
 import sinon from 'sinon'
 import tk from 'timekeeper'
 import moment from 'moment'
-import { Project } from '../../../../app/src/models/Project.mjs'
-import { DeletedProject } from '../../../../app/src/models/DeletedProject.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
 import mongodb from 'mongodb-legacy'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
 const modulePath = '../../../../app/src/Features/Project/ProjectDeleter'
 
+const { Project, DeletedProject } = indirectlyImportModels([
+  'Project',
+  'DeletedProject',
+])
 const { ObjectId, ReadPreference } = mongodb
 vi.mock('../../../../app/src/Features/Errors/Errors.js', () =>
   vi.importActual('../../../../app/src/Features/Errors/Errors.js')
diff --git a/services/web/test/unit/src/Project/ProjectEntityMongoUpdateHandler.test.mjs b/services/web/test/unit/src/Project/ProjectEntityMongoUpdateHandler.test.mjs
index ab400edc59..4e8f9e86d1 100644
--- a/services/web/test/unit/src/Project/ProjectEntityMongoUpdateHandler.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectEntityMongoUpdateHandler.test.mjs
@@ -3,8 +3,9 @@ import sinon from 'sinon'
 import tk from 'timekeeper'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
 import mongodb from 'mongodb-legacy'
-import { Project } from '../../../../app/src/models/Project.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
 
+const { Project } = indirectlyImportModels(['Project'])
 const { ObjectId } = mongodb
 
 vi.mock('../../../../app/src/Features/Errors/Errors.js', () =>
diff --git a/services/web/test/unit/src/Project/ProjectHistoryHandler.test.mjs b/services/web/test/unit/src/Project/ProjectHistoryHandler.test.mjs
index 6937b3c9a2..e3b94e09b5 100644
--- a/services/web/test/unit/src/Project/ProjectHistoryHandler.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectHistoryHandler.test.mjs
@@ -33,7 +33,7 @@ describe('ProjectHistoryHandler', function () {
       default: (ctx.Settings = {}),
     }))
 
-    vi.doMock('../../../../app/src/models/Project.mjs', () => ({
+    vi.doMock('../../../../app/src/models/Project.js', () => ({
       Project: ctx.ProjectModel,
     }))
 
diff --git a/services/web/test/unit/src/Referal/ReferalAllocator.test.mjs b/services/web/test/unit/src/Referal/ReferalAllocator.test.mjs
index 423d707735..ae5e9bb27f 100644
--- a/services/web/test/unit/src/Referal/ReferalAllocator.test.mjs
+++ b/services/web/test/unit/src/Referal/ReferalAllocator.test.mjs
@@ -5,7 +5,7 @@ const modulePath = '../../../../app/src/Features/Referal/ReferalAllocator.mjs'
 
 describe('ReferalAllocator', function () {
   beforeEach(async function (ctx) {
-    vi.doMock('../../../../app/src/models/User.mjs', () => ({
+    vi.doMock('../../../../app/src/models/User.js', () => ({
       User: (ctx.User = {}),
     }))
 
diff --git a/services/web/test/unit/src/Security/OneTimeTokenHandler.sequential.test.mjs b/services/web/test/unit/src/Security/OneTimeTokenHandlerTests.js
similarity index 84%
rename from services/web/test/unit/src/Security/OneTimeTokenHandler.sequential.test.mjs
rename to services/web/test/unit/src/Security/OneTimeTokenHandlerTests.js
index df412f2d39..b48dffe237 100644
--- a/services/web/test/unit/src/Security/OneTimeTokenHandler.sequential.test.mjs
+++ b/services/web/test/unit/src/Security/OneTimeTokenHandlerTests.js
@@ -1,28 +1,24 @@
-import sinon from 'sinon'
-import { beforeAll, beforeEach, describe, expect, it, vi } from 'vitest'
-import Errors from '../../../../app/src/Features/Errors/Errors.js'
-import {
+const sinon = require('sinon')
+const { expect } = require('chai')
+const Errors = require('../../../../app/src/Features/Errors/Errors')
+const {
   connectionPromise,
   cleanupTestDatabase,
-} from '../../../../app/src/infrastructure/mongodb.js'
-import OneTimeTokenHandler from '../../../../app/src/Features/Security/OneTimeTokenHandler.mjs'
-
-vi.mock('../../../../app/src/Features/Errors/Errors.js', () =>
-  vi.importActual('../../../../app/src/Features/Errors/Errors.js')
-)
+} = require('../../../../app/src/infrastructure/mongodb')
+const OneTimeTokenHandler = require('../../../../app/src/Features/Security/OneTimeTokenHandler')
 
 describe('OneTimeTokenHandler', function () {
-  beforeAll(async function () {
+  before(async function () {
     await connectionPromise
   })
   beforeEach(cleanupTestDatabase)
 
-  beforeEach(function (ctx) {
-    ctx.clock = sinon.useFakeTimers()
+  beforeEach(function () {
+    this.clock = sinon.useFakeTimers()
   })
 
-  afterEach(function (ctx) {
-    ctx.clock.restore()
+  afterEach(function () {
+    this.clock.restore()
   })
 
   describe('getNewToken', function () {
@@ -38,30 +34,30 @@ describe('OneTimeTokenHandler', function () {
       expect(data).to.equal('mock-data-to-store')
     })
 
-    it('expires the generated token after 1 hour', async function (ctx) {
+    it('expires the generated token after 1 hour', async function () {
       const token = await OneTimeTokenHandler.promises.getNewToken(
         'password',
         'mock-data-to-store'
       )
-      ctx.clock.tick('25:00:00')
+      this.clock.tick('25:00:00')
       await expect(
         OneTimeTokenHandler.promises.peekValueFromToken('password', token)
       ).to.be.rejectedWith(Errors.NotFoundError)
     })
 
-    it('accepts an expiresIn parameter', async function (ctx) {
+    it('accepts an expiresIn parameter', async function () {
       const token = await OneTimeTokenHandler.promises.getNewToken(
         'password',
         'mock-data-to-store',
         { expiresIn: 42 }
       )
-      ctx.clock.tick('00:30')
+      this.clock.tick('00:30')
       const { data } = await OneTimeTokenHandler.promises.peekValueFromToken(
         'password',
         token
       )
       expect(data).to.equal('mock-data-to-store')
-      ctx.clock.tick('00:15')
+      this.clock.tick('00:15')
       await expect(
         OneTimeTokenHandler.promises.peekValueFromToken('password', token)
       ).to.be.rejectedWith(Errors.NotFoundError)
diff --git a/services/web/test/unit/src/Subscription/PaymentProviderEntities.test.mjs b/services/web/test/unit/src/Subscription/PaymentProviderEntities.test.mjs
index 8b60574599..380d1b42e2 100644
--- a/services/web/test/unit/src/Subscription/PaymentProviderEntities.test.mjs
+++ b/services/web/test/unit/src/Subscription/PaymentProviderEntities.test.mjs
@@ -4,7 +4,7 @@ import Errors from '../../../../app/src/Features/Subscription/Errors.js'
 
 import PaymentProviderEntities from '../../../../app/src/Features/Subscription/PaymentProviderEntities.mjs'
 import { AI_ADD_ON_CODE } from '../../../../app/src/Features/Subscription/AiHelper.js'
-import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.mjs'
+import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.js'
 
 const {
   PaymentProviderSubscriptionChangeRequest,
diff --git a/services/web/test/unit/src/Subscription/SubscriptionController.test.mjs b/services/web/test/unit/src/Subscription/SubscriptionController.test.mjs
index 1d4e6ec607..103acc862b 100644
--- a/services/web/test/unit/src/Subscription/SubscriptionController.test.mjs
+++ b/services/web/test/unit/src/Subscription/SubscriptionController.test.mjs
@@ -3,7 +3,7 @@ import sinon from 'sinon'
 import MockRequest from '../helpers/MockRequest.js'
 import MockResponse from '../helpers/MockResponse.js'
 import SubscriptionErrors from '../../../../app/src/Features/Subscription/Errors.js'
-import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.mjs'
+import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.js'
 import { AI_ADD_ON_CODE } from '../../../../app/src/Features/Subscription/AiHelper.js'
 
 const modulePath =
diff --git a/services/web/test/unit/src/Subscription/SubscriptionHandler.test.mjs b/services/web/test/unit/src/Subscription/SubscriptionHandler.test.mjs
index 2a3ce3a33a..7f0290f4a0 100644
--- a/services/web/test/unit/src/Subscription/SubscriptionHandler.test.mjs
+++ b/services/web/test/unit/src/Subscription/SubscriptionHandler.test.mjs
@@ -1,7 +1,7 @@
 import { expect, vi } from 'vitest'
 import sinon from 'sinon'
 import PaymentProviderEntities from '../../../../app/src/Features/Subscription/PaymentProviderEntities.mjs'
-import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.mjs'
+import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.js'
 
 const { PaymentProviderSubscription } = PaymentProviderEntities
 const MODULE_PATH =
diff --git a/services/web/test/unit/src/Subscription/SubscriptionHelper.test.mjs b/services/web/test/unit/src/Subscription/SubscriptionHelperTests.js
similarity index 61%
rename from services/web/test/unit/src/Subscription/SubscriptionHelper.test.mjs
rename to services/web/test/unit/src/Subscription/SubscriptionHelperTests.js
index a77800361a..fae3e6e2e6 100644
--- a/services/web/test/unit/src/Subscription/SubscriptionHelper.test.mjs
+++ b/services/web/test/unit/src/Subscription/SubscriptionHelperTests.js
@@ -1,5 +1,6 @@
-import { vi, expect } from 'vitest'
-import sinon from 'sinon'
+const SandboxedModule = require('sandboxed-module')
+const { expect } = require('chai')
+const sinon = require('sinon')
 const modulePath =
   '../../../../app/src/Features/Subscription/SubscriptionHelper'
 
@@ -30,9 +31,9 @@ const plans = {
 }
 
 describe('SubscriptionHelper', function () {
-  beforeEach(async function (ctx) {
-    ctx.clock = sinon.useFakeTimers(new Date('2023-06-15T10:00:00Z'))
-    ctx.Subscription = {
+  beforeEach(function () {
+    this.clock = sinon.useFakeTimers(new Date('2023-06-15T10:00:00Z'))
+    this.Subscription = {
       findOne: sinon.stub().returns({
         exec: sinon.stub().resolves(),
       }),
@@ -48,91 +49,86 @@ describe('SubscriptionHelper', function () {
         exec: sinon.stub().resolves(),
       }),
     }
-    ctx.INITIAL_LICENSE_SIZE = 2
-    ctx.settings = {
+    this.INITIAL_LICENSE_SIZE = 2
+    this.settings = {
       groupPlanModalOptions: {},
     }
-    ctx.GroupPlansData = {
+    this.GroupPlansData = {
       enterprise: {
         collaborator: {
           CHF: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 1000,
             },
           },
           DKK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 2000,
             },
           },
           SEK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 3000,
             },
           },
           NOK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 4000,
             },
           },
           USD: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 5000,
             },
           },
         },
         professional: {
           CHF: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 10000,
             },
           },
           DKK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 20000,
             },
           },
           SEK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 30000,
             },
           },
           NOK: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 40000,
             },
           },
           USD: {
-            [ctx.INITIAL_LICENSE_SIZE]: {
+            [this.INITIAL_LICENSE_SIZE]: {
               price_in_cents: 50000,
             },
           },
         },
       },
     }
-
-    vi.doMock('../../../../app/src/models/Subscription', () => ({
-      Subscription: ctx.Subscription,
-    }))
-
-    vi.doMock('@overleaf/settings', () => ({
-      default: ctx.settings,
-    }))
-
-    vi.doMock(
-      '../../../../app/src/Features/Subscription/GroupPlansData',
-      () => ({
-        default: ctx.GroupPlansData,
-      })
-    )
-
-    ctx.SubscriptionHelper = (await import(modulePath)).default
+    this.SubscriptionHelper = SandboxedModule.require(modulePath, {
+      globals: {
+        Date: this.clock.Date,
+      },
+      requires: {
+        '../../models/Subscription': {
+          Subscription: this.Subscription,
+        },
+        '@overleaf/settings': this.settings,
+        './GroupPlansData': this.GroupPlansData,
+      },
+    })
   })
 
   describe('shouldPlanChangeAtTermEnd', function () {
-    it('should return false if isInTrial is true', function (ctx) {
+    it('should return false if isInTrial is true', function () {
       const isInTrial = true
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.expensive,
         plans.cheaper,
         isInTrial
@@ -140,9 +136,9 @@ describe('SubscriptionHelper', function () {
       expect(changeAtTermEnd).to.be.false
     })
 
-    it('should return true if the new plan is less expensive', function (ctx) {
+    it('should return true if the new plan is less expensive', function () {
       const isInTrial = false
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.expensive,
         plans.cheaper,
         isInTrial
@@ -150,9 +146,9 @@ describe('SubscriptionHelper', function () {
       expect(changeAtTermEnd).to.be.true
     })
 
-    it('should return false if the new plan is more exepensive', function (ctx) {
+    it('should return false if the new plan is more exepensive', function () {
       const isInTrial = false
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.cheaper,
         plans.expensive,
         isInTrial
@@ -160,10 +156,10 @@ describe('SubscriptionHelper', function () {
       expect(changeAtTermEnd).to.be.false
     })
 
-    it('should return false if the new plan is the same price', function (ctx) {
+    it('should return false if the new plan is the same price', function () {
       const isInTrial = false
 
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.cheaper,
         plans.alsoCheap,
         isInTrial
@@ -171,10 +167,10 @@ describe('SubscriptionHelper', function () {
       expect(changeAtTermEnd).to.be.false
     })
 
-    it('should return false if the change is from an individual plan to a more expensive group plan', function (ctx) {
+    it('should return false if the change is from an individual plan to a more expensive group plan', function () {
       const isInTrial = false
 
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.expensive,
         plans.expensiveGroup,
         isInTrial
@@ -182,10 +178,10 @@ describe('SubscriptionHelper', function () {
       expect(changeAtTermEnd).to.be.false
     })
 
-    it('should return true if the change is from an individual plan to a cheaper group plan', function (ctx) {
+    it('should return true if the change is from an individual plan to a cheaper group plan', function () {
       const isInTrial = false
 
-      const changeAtTermEnd = ctx.SubscriptionHelper.shouldPlanChangeAtTermEnd(
+      const changeAtTermEnd = this.SubscriptionHelper.shouldPlanChangeAtTermEnd(
         plans.expensive,
         plans.cheapGroup,
         isInTrial
@@ -196,9 +192,12 @@ describe('SubscriptionHelper', function () {
 
   describe('generateInitialLocalizedGroupPrice', function () {
     describe('CHF currency', function () {
-      it('should return the correct localized price for every plan', function (ctx) {
+      it('should return the correct localized price for every plan', function () {
         const localizedPrice =
-          ctx.SubscriptionHelper.generateInitialLocalizedGroupPrice('CHF', 'fr')
+          this.SubscriptionHelper.generateInitialLocalizedGroupPrice(
+            'CHF',
+            'fr'
+          )
 
         expect(localizedPrice).to.deep.equal({
           price: {
@@ -214,9 +213,12 @@ describe('SubscriptionHelper', function () {
     })
 
     describe('DKK currency', function () {
-      it('should return the correct localized price for every plan', function (ctx) {
+      it('should return the correct localized price for every plan', function () {
         const localizedPrice =
-          ctx.SubscriptionHelper.generateInitialLocalizedGroupPrice('DKK', 'da')
+          this.SubscriptionHelper.generateInitialLocalizedGroupPrice(
+            'DKK',
+            'da'
+          )
 
         expect(localizedPrice).to.deep.equal({
           price: {
@@ -232,9 +234,12 @@ describe('SubscriptionHelper', function () {
     })
 
     describe('SEK currency', function () {
-      it('should return the correct localized price for every plan', function (ctx) {
+      it('should return the correct localized price for every plan', function () {
         const localizedPrice =
-          ctx.SubscriptionHelper.generateInitialLocalizedGroupPrice('SEK', 'sv')
+          this.SubscriptionHelper.generateInitialLocalizedGroupPrice(
+            'SEK',
+            'sv'
+          )
 
         expect(localizedPrice).to.deep.equal({
           price: {
@@ -250,9 +255,9 @@ describe('SubscriptionHelper', function () {
     })
 
     describe('NOK currency', function () {
-      it('should return the correct localized price for every plan', function (ctx) {
+      it('should return the correct localized price for every plan', function () {
         const localizedPrice =
-          ctx.SubscriptionHelper.generateInitialLocalizedGroupPrice(
+          this.SubscriptionHelper.generateInitialLocalizedGroupPrice(
             'NOK',
             // there seem to be possible inconsistencies with the CI
             // maybe it depends on what languages are installed on the server?
@@ -273,9 +278,12 @@ describe('SubscriptionHelper', function () {
     })
 
     describe('other supported currencies', function () {
-      it('should return the correct localized price for every plan', function (ctx) {
+      it('should return the correct localized price for every plan', function () {
         const localizedPrice =
-          ctx.SubscriptionHelper.generateInitialLocalizedGroupPrice('USD', 'en')
+          this.SubscriptionHelper.generateInitialLocalizedGroupPrice(
+            'USD',
+            'en'
+          )
 
         expect(localizedPrice).to.deep.equal({
           price: {
@@ -292,219 +300,235 @@ describe('SubscriptionHelper', function () {
   })
 
   describe('isPaidSubscription', function () {
-    it('should return true for a subscription with a recurly subscription id', function (ctx) {
-      const result = ctx.SubscriptionHelper.isPaidSubscription({
+    it('should return true for a subscription with a recurly subscription id', function () {
+      const result = this.SubscriptionHelper.isPaidSubscription({
         recurlySubscription_id: 'some-id',
       })
       expect(result).to.be.true
     })
 
-    it('should return true for a subscription with a stripe subscription id', function (ctx) {
-      const result = ctx.SubscriptionHelper.isPaidSubscription({
+    it('should return true for a subscription with a stripe subscription id', function () {
+      const result = this.SubscriptionHelper.isPaidSubscription({
         paymentProvider: { subscriptionId: 'some-id' },
       })
       expect(result).to.be.true
     })
 
-    it('should return false for a free subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isPaidSubscription({})
+    it('should return false for a free subscription', function () {
+      const result = this.SubscriptionHelper.isPaidSubscription({})
       expect(result).to.be.false
     })
 
-    it('should return false for a missing subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isPaidSubscription()
+    it('should return false for a missing subscription', function () {
+      const result = this.SubscriptionHelper.isPaidSubscription()
       expect(result).to.be.false
     })
   })
 
   describe('isIndividualActivePaidSubscription', function () {
-    it('should return true for an active recurly subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        recurlyStatus: { state: 'active' },
-        recurlySubscription_id: 'some-id',
-      })
+    it('should return true for an active recurly subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          recurlyStatus: { state: 'active' },
+          recurlySubscription_id: 'some-id',
+        }
+      )
       expect(result).to.be.true
     })
 
-    it('should return true for an active stripe subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        paymentProvider: { subscriptionId: 'sub_123', state: 'active' },
-      })
+    it('should return true for an active stripe subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          paymentProvider: { subscriptionId: 'sub_123', state: 'active' },
+        }
+      )
       expect(result).to.be.true
     })
 
-    it('should return false for a canceled recurly subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        recurlyStatus: { state: 'canceled' },
-        recurlySubscription_id: 'some-id',
-      })
+    it('should return false for a canceled recurly subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          recurlyStatus: { state: 'canceled' },
+          recurlySubscription_id: 'some-id',
+        }
+      )
       expect(result).to.be.false
     })
 
-    it('should return false for a canceled stripe subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        paymentProvider: { state: 'canceled', subscriptionId: 'sub_123' },
-      })
+    it('should return false for a canceled stripe subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          paymentProvider: { state: 'canceled', subscriptionId: 'sub_123' },
+        }
+      )
       expect(result).to.be.false
     })
 
-    it('should return false for a group plan subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: true,
-        recurlyStatus: { state: 'active' },
-        recurlySubscription_id: 'some-id',
-      })
+    it('should return false for a group plan subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: true,
+          recurlyStatus: { state: 'active' },
+          recurlySubscription_id: 'some-id',
+        }
+      )
       expect(result).to.be.false
     })
 
-    it('should return false for a free subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription(
+    it('should return false for a free subscription', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
         {}
       )
       expect(result).to.be.false
     })
 
-    it('should return false for a subscription with an empty string for recurlySubscription_id', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        recurlySubscription_id: '',
-        recurlyStatus: { state: 'active' },
-      })
+    it('should return false for a subscription with an empty string for recurlySubscription_id', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          recurlySubscription_id: '',
+          recurlyStatus: { state: 'active' },
+        }
+      )
       expect(result).to.be.false
     })
 
-    it('should return false for a subscription with an empty string for paymentProvider.subscriptionId', function (ctx) {
-      const result = ctx.SubscriptionHelper.isIndividualActivePaidSubscription({
-        groupPlan: false,
-        paymentProvider: { state: 'active', subscriptionId: '' },
-      })
+    it('should return false for a subscription with an empty string for paymentProvider.subscriptionId', function () {
+      const result = this.SubscriptionHelper.isIndividualActivePaidSubscription(
+        {
+          groupPlan: false,
+          paymentProvider: { state: 'active', subscriptionId: '' },
+        }
+      )
       expect(result).to.be.false
     })
 
-    it('should return false for a missing subscription', function (ctx) {
-      const result = ctx.SubscriptionHelper.isPaidSubscription()
+    it('should return false for a missing subscription', function () {
+      const result = this.SubscriptionHelper.isPaidSubscription()
       expect(result).to.be.false
     })
   })
 
   describe('getPaymentProviderSubscriptionId', function () {
-    it('should return the recurly subscription id if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaymentProviderSubscriptionId({
+    it('should return the recurly subscription id if it exists', function () {
+      const result = this.SubscriptionHelper.getPaymentProviderSubscriptionId({
         recurlySubscription_id: 'some-id',
       })
       expect(result).to.equal('some-id')
     })
 
-    it('should return the payment provider subscription id if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaymentProviderSubscriptionId({
+    it('should return the payment provider subscription id if it exists', function () {
+      const result = this.SubscriptionHelper.getPaymentProviderSubscriptionId({
         paymentProvider: { subscriptionId: 'sub_123' },
       })
       expect(result).to.equal('sub_123')
     })
 
-    it('should return null if no subscription id exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaymentProviderSubscriptionId({})
+    it('should return null if no subscription id exists', function () {
+      const result = this.SubscriptionHelper.getPaymentProviderSubscriptionId(
+        {}
+      )
       expect(result).to.be.null
     })
   })
 
   describe('getPaidSubscriptionState', function () {
-    it('should return the recurly state if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaidSubscriptionState({
+    it('should return the recurly state if it exists', function () {
+      const result = this.SubscriptionHelper.getPaidSubscriptionState({
         recurlyStatus: { state: 'active' },
       })
       expect(result).to.equal('active')
     })
 
-    it('should return the payment provider state if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaidSubscriptionState({
+    it('should return the payment provider state if it exists', function () {
+      const result = this.SubscriptionHelper.getPaidSubscriptionState({
         paymentProvider: { state: 'active' },
       })
       expect(result).to.equal('active')
     })
 
-    it('should return null if no state exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getPaidSubscriptionState({})
+    it('should return null if no state exists', function () {
+      const result = this.SubscriptionHelper.getPaidSubscriptionState({})
       expect(result).to.be.null
     })
   })
 
   describe('getSubscriptionTrialStartedAt', function () {
-    it('should return the recurly trial start date if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialStartedAt({
+    it('should return the recurly trial start date if it exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialStartedAt({
         recurlySubscription_id: 'some-id',
         recurlyStatus: { trialStartedAt: new Date('2023-01-01') },
       })
       expect(result).to.deep.equal(new Date('2023-01-01'))
     })
 
-    it('should return the payment provider trial start date if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialStartedAt({
+    it('should return the payment provider trial start date if it exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialStartedAt({
         recurlyStatus: {},
         paymentProvider: { trialStartedAt: new Date('2023-01-01') },
       })
       expect(result).to.deep.equal(new Date('2023-01-01'))
     })
 
-    it('should return undefined if no trial start date exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialStartedAt({})
+    it('should return undefined if no trial start date exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialStartedAt({})
       expect(result).to.be.undefined
     })
   })
 
   describe('getSubscriptionTrialEndsAt', function () {
-    it('should return the recurly trial end date if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialEndsAt({
+    it('should return the recurly trial end date if it exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialEndsAt({
         recurlySubscription_id: 'some-id',
         recurlyStatus: { trialEndsAt: new Date('2023-01-01') },
       })
       expect(result).to.deep.equal(new Date('2023-01-01'))
     })
 
-    it('should return the payment provider trial end date if it exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialEndsAt({
+    it('should return the payment provider trial end date if it exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialEndsAt({
         recurlyStatus: {},
         paymentProvider: { trialEndsAt: new Date('2023-01-01') },
       })
       expect(result).to.deep.equal(new Date('2023-01-01'))
     })
 
-    it('should return undefined if no trial end date exists', function (ctx) {
-      const result = ctx.SubscriptionHelper.getSubscriptionTrialEndsAt({})
+    it('should return undefined if no trial end date exists', function () {
+      const result = this.SubscriptionHelper.getSubscriptionTrialEndsAt({})
       expect(result).to.be.undefined
     })
   })
 
   describe('isInTrial', function () {
-    it('should return false if trialEndsAt is null', function (ctx) {
-      const result = ctx.SubscriptionHelper.isInTrial(null)
+    it('should return false if trialEndsAt is null', function () {
+      const result = this.SubscriptionHelper.isInTrial(null)
       expect(result).to.be.false
     })
 
-    it('should return false if trialEndsAt is before now', function (ctx) {
+    it('should return false if trialEndsAt is before now', function () {
       const tenDaysAgo = new Date()
       tenDaysAgo.setDate(tenDaysAgo.getDate() - 10)
-      const result = ctx.SubscriptionHelper.isInTrial(tenDaysAgo)
+      const result = this.SubscriptionHelper.isInTrial(tenDaysAgo)
       expect(result).to.be.false
     })
 
-    it('should return true if trialEndsAt is after now', function (ctx) {
+    it('should return true if trialEndsAt is after now', function () {
       const tenDaysFromNow = new Date()
       tenDaysFromNow.setDate(tenDaysFromNow.getDate() + 10)
-      const result = ctx.SubscriptionHelper.isInTrial(tenDaysFromNow)
+      const result = this.SubscriptionHelper.isInTrial(tenDaysFromNow)
       expect(result).to.be.true
     })
   })
 
   describe('recomputeSubscriptionState', function () {
-    beforeEach(function (ctx) {
-      ctx.clock.now = new Date('2023-06-15T10:00:00Z')
+    beforeEach(function () {
+      this.clock.now = new Date('2023-06-15T10:00:00Z')
 
-      ctx.baseSubscription = {
+      this.baseSubscription = {
         _id: 'subscription_id',
         paymentProvider: {
           service: 'stripe-test',
@@ -517,16 +541,16 @@ describe('SubscriptionHelper', function () {
     })
 
     describe('when subscription has no paymentProvider subscriptionId', function () {
-      it('should return subscription unchanged', async function (ctx) {
+      it('should return subscription unchanged', async function () {
         const subscription = { _id: 'subscription_id' }
         const result =
-          await ctx.SubscriptionHelper.recomputeSubscriptionState(subscription)
+          await this.SubscriptionHelper.recomputeSubscriptionState(subscription)
         expect(result).to.equal(subscription)
       })
     })
 
     describe('when subscription has no pausePeriodStart', function () {
-      it('should return subscription unchanged', async function (ctx) {
+      it('should return subscription unchanged', async function () {
         const subscription = {
           _id: 'subscription_id',
           paymentProvider: {
@@ -535,22 +559,22 @@ describe('SubscriptionHelper', function () {
           },
         }
         const result =
-          await ctx.SubscriptionHelper.recomputeSubscriptionState(subscription)
+          await this.SubscriptionHelper.recomputeSubscriptionState(subscription)
         expect(result).to.equal(subscription)
       })
     })
 
     describe('when subscription should be paused', function () {
       describe('and current state is active', function () {
-        it('should change state to paused', async function (ctx) {
-          const subscription = { ...ctx.baseSubscription }
+        it('should change state to paused', async function () {
+          const subscription = { ...this.baseSubscription }
           const result =
-            await ctx.SubscriptionHelper.recomputeSubscriptionState(
+            await this.SubscriptionHelper.recomputeSubscriptionState(
               subscription
             )
 
           expect(result.paymentProvider.state).to.equal('paused')
-          expect(ctx.Subscription.updateOne).to.have.been.calledWith(
+          expect(this.Subscription.updateOne).to.have.been.calledWith(
             { _id: 'subscription_id' },
             { 'paymentProvider.state': 'paused' }
           )
@@ -558,64 +582,64 @@ describe('SubscriptionHelper', function () {
       })
 
       describe('and current state is already paused', function () {
-        it('should not change state', async function (ctx) {
+        it('should not change state', async function () {
           const subscription = {
-            ...ctx.baseSubscription,
+            ...this.baseSubscription,
             paymentProvider: {
-              ...ctx.baseSubscription.paymentProvider,
+              ...this.baseSubscription.paymentProvider,
               state: 'paused',
             },
           }
           const result =
-            await ctx.SubscriptionHelper.recomputeSubscriptionState(
+            await this.SubscriptionHelper.recomputeSubscriptionState(
               subscription
             )
 
           expect(result.paymentProvider.state).to.equal('paused')
-          expect(ctx.Subscription.updateOne.called).to.be.false
+          expect(this.Subscription.updateOne.called).to.be.false
         })
       })
     })
 
     describe('when subscription should not be paused', function () {
       describe('before pause period starts', function () {
-        beforeEach(function (ctx) {
-          ctx.clock.now = new Date('2023-06-15T08:00:00Z')
+        beforeEach(function () {
+          this.clock.now = new Date('2023-06-15T08:00:00Z')
         })
 
-        it('should keep active state unchanged', async function (ctx) {
-          const subscription = { ...ctx.baseSubscription }
+        it('should keep active state unchanged', async function () {
+          const subscription = { ...this.baseSubscription }
           const result =
-            await ctx.SubscriptionHelper.recomputeSubscriptionState(
+            await this.SubscriptionHelper.recomputeSubscriptionState(
               subscription
             )
 
           expect(result.paymentProvider.state).to.equal('active')
-          expect(ctx.Subscription.updateOne.called).to.be.false
+          expect(this.Subscription.updateOne.called).to.be.false
         })
       })
 
       describe('after pause period ends', function () {
-        beforeEach(function (ctx) {
-          ctx.clock.now = new Date('2023-06-15T12:00:00Z')
+        beforeEach(function () {
+          this.clock.now = new Date('2023-06-15T12:00:00Z')
         })
 
         describe('and current state is paused', function () {
-          it('should change state to active', async function (ctx) {
+          it('should change state to active', async function () {
             const subscription = {
-              ...ctx.baseSubscription,
+              ...this.baseSubscription,
               paymentProvider: {
-                ...ctx.baseSubscription.paymentProvider,
+                ...this.baseSubscription.paymentProvider,
                 state: 'paused',
               },
             }
             const result =
-              await ctx.SubscriptionHelper.recomputeSubscriptionState(
+              await this.SubscriptionHelper.recomputeSubscriptionState(
                 subscription
               )
 
             expect(result.paymentProvider.state).to.equal('active')
-            expect(ctx.Subscription.updateOne).to.have.been.calledWith(
+            expect(this.Subscription.updateOne).to.have.been.calledWith(
               { _id: 'subscription_id' },
               { 'paymentProvider.state': 'active' }
             )
@@ -623,48 +647,48 @@ describe('SubscriptionHelper', function () {
         })
 
         describe('and current state is already active', function () {
-          it('should keep state unchanged', async function (ctx) {
-            const subscription = { ...ctx.baseSubscription }
+          it('should keep state unchanged', async function () {
+            const subscription = { ...this.baseSubscription }
             const result =
-              await ctx.SubscriptionHelper.recomputeSubscriptionState(
+              await this.SubscriptionHelper.recomputeSubscriptionState(
                 subscription
               )
 
             expect(result.paymentProvider.state).to.equal('active')
-            expect(ctx.Subscription.updateOne.called).to.be.false
+            expect(this.Subscription.updateOne.called).to.be.false
           })
         })
       })
     })
 
     describe('when subscription has no pausePeriodEnd (indefinite pause)', function () {
-      beforeEach(function (ctx) {
-        ctx.baseSubscription.paymentProvider.pausePeriodEnd = undefined
+      beforeEach(function () {
+        this.baseSubscription.paymentProvider.pausePeriodEnd = undefined
       })
 
-      it('should not transition to paused state when pausePeriodEnd is missing', async function (ctx) {
-        const subscription = { ...ctx.baseSubscription }
+      it('should not transition to paused state when pausePeriodEnd is missing', async function () {
+        const subscription = { ...this.baseSubscription }
         const result =
-          await ctx.SubscriptionHelper.recomputeSubscriptionState(subscription)
+          await this.SubscriptionHelper.recomputeSubscriptionState(subscription)
 
         expect(result.paymentProvider.state).to.equal('active')
-        expect(ctx.Subscription.updateOne.called).to.be.false
+        expect(this.Subscription.updateOne.called).to.be.false
       })
 
-      it('should keep paused state when already paused and no end date', async function (ctx) {
+      it('should keep paused state when already paused and no end date', async function () {
         const subscription = {
-          ...ctx.baseSubscription,
+          ...this.baseSubscription,
           paymentProvider: {
-            ...ctx.baseSubscription.paymentProvider,
+            ...this.baseSubscription.paymentProvider,
             state: 'paused',
             pausePeriodEnd: undefined,
           },
         }
         const result =
-          await ctx.SubscriptionHelper.recomputeSubscriptionState(subscription)
+          await this.SubscriptionHelper.recomputeSubscriptionState(subscription)
 
         expect(result.paymentProvider.state).to.equal('paused')
-        expect(ctx.Subscription.updateOne.called).to.be.false
+        expect(this.Subscription.updateOne.called).to.be.false
       })
     })
   })
diff --git a/services/web/test/unit/src/Subscription/SubscriptionViewModelBuilder.test.mjs b/services/web/test/unit/src/Subscription/SubscriptionViewModelBuilder.test.mjs
index 336679b070..90737cf3df 100644
--- a/services/web/test/unit/src/Subscription/SubscriptionViewModelBuilder.test.mjs
+++ b/services/web/test/unit/src/Subscription/SubscriptionViewModelBuilder.test.mjs
@@ -1,7 +1,7 @@
 import { vi, assert } from 'vitest'
 import sinon from 'sinon'
 import PaymentProviderEntities from '../../../../app/src/Features/Subscription/PaymentProviderEntities.mjs'
-import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.mjs'
+import SubscriptionHelper from '../../../../app/src/Features/Subscription/SubscriptionHelper.js'
 
 const {
   PaymentProviderAccount,
diff --git a/services/web/test/unit/src/Tags/TagsHandler.test.mjs b/services/web/test/unit/src/Tags/TagsHandler.test.mjs
index f7562f787a..b1f2fdb545 100644
--- a/services/web/test/unit/src/Tags/TagsHandler.test.mjs
+++ b/services/web/test/unit/src/Tags/TagsHandler.test.mjs
@@ -1,8 +1,8 @@
 import { vi, expect } from 'vitest'
 import sinon from 'sinon'
+import { Tag } from '../helpers/models/Tag.js'
 import mongodb from 'mongodb-legacy'
 import path from 'node:path'
-import { Tag } from '../../../../app/src/models/Tag.mjs'
 const { ObjectId } = mongodb
 
 const modulePath = path.join(
diff --git a/services/web/test/unit/src/ThirdPartyDataStore/TpdsProjectFlusher.test.mjs b/services/web/test/unit/src/ThirdPartyDataStore/TpdsProjectFlusher.test.mjs
index 11aa7bc7bd..64c7782c3f 100644
--- a/services/web/test/unit/src/ThirdPartyDataStore/TpdsProjectFlusher.test.mjs
+++ b/services/web/test/unit/src/ThirdPartyDataStore/TpdsProjectFlusher.test.mjs
@@ -1,7 +1,9 @@
 import { vi, expect } from 'vitest'
 import sinon from 'sinon'
 import mongodb from 'mongodb-legacy'
-import { Project } from '../../../../app/src/models/Project.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
+
+const { Project } = indirectlyImportModels(['Project'])
 
 const { ObjectId } = mongodb
 
diff --git a/services/web/test/unit/src/User/UserAuditLogHandler.test.mjs b/services/web/test/unit/src/User/UserAuditLogHandler.test.mjs
index 7bda3b03f8..7e3bb5bbb4 100644
--- a/services/web/test/unit/src/User/UserAuditLogHandler.test.mjs
+++ b/services/web/test/unit/src/User/UserAuditLogHandler.test.mjs
@@ -1,7 +1,9 @@
 import { vi, expect } from 'vitest'
 import sinon from 'sinon'
 import mongodb from 'mongodb-legacy'
-import { UserAuditLogEntry } from '../../../../app/src/models/UserAuditLogEntry.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
+
+const { UserAuditLogEntry } = indirectlyImportModels(['UserAuditLogEntry'])
 
 const { ObjectId } = mongodb
 
diff --git a/services/web/test/unit/src/User/UserDeleter.test.mjs b/services/web/test/unit/src/User/UserDeleter.test.mjs
index 5e41c89a80..3baf70edd3 100644
--- a/services/web/test/unit/src/User/UserDeleter.test.mjs
+++ b/services/web/test/unit/src/User/UserDeleter.test.mjs
@@ -4,8 +4,9 @@ import tk from 'timekeeper'
 import moment from 'moment'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
 import mongoose from 'mongoose'
-import { DeletedUser } from '../../../../app/src/models/DeletedUser.mjs'
-import { User } from '../../../../app/src/models/User.mjs'
+import indirectlyImportModels from '../helpers/indirectlyImportModels.js'
+
+const { User, DeletedUser } = indirectlyImportModels(['User', 'DeletedUser'])
 
 const ObjectId = mongoose.Types.ObjectId
 
diff --git a/services/web/test/unit/src/User/UserEmailsConfirmationHandler.test.mjs b/services/web/test/unit/src/User/UserEmailsConfirmationHandler.test.mjs
index 6ed79d7874..9c23805a9c 100644
--- a/services/web/test/unit/src/User/UserEmailsConfirmationHandler.test.mjs
+++ b/services/web/test/unit/src/User/UserEmailsConfirmationHandler.test.mjs
@@ -10,7 +10,7 @@ import { vi, expect } from 'vitest'
 
 import sinon from 'sinon'
 import Errors from '../../../../app/src/Features/Errors/Errors.js'
-import EmailHelper from '../../../../app/src/Features/Helpers/EmailHelper.mjs'
+import EmailHelper from '../../../../app/src/Features/Helpers/EmailHelper.js'
 
 const modulePath =
   '../../../../app/src/Features/User/UserEmailsConfirmationHandler'
diff --git a/services/web/test/unit/src/User/UserRegistrationHandler.test.mjs b/services/web/test/unit/src/User/UserRegistrationHandler.test.mjs
index ce1f478fbf..f8e7e50826 100644
--- a/services/web/test/unit/src/User/UserRegistrationHandler.test.mjs
+++ b/services/web/test/unit/src/User/UserRegistrationHandler.test.mjs
@@ -1,7 +1,7 @@
 import { vi, expect } from 'vitest'
 import assert from 'assert'
 import sinon from 'sinon'
-import EmailHelper from '../../../../app/src/Features/Helpers/EmailHelper.mjs'
+import EmailHelper from '../../../../app/src/Features/Helpers/EmailHelper.js'
 
 const modulePath = '../../../../app/src/Features/User/UserRegistrationHandler'
 
diff --git a/services/web/test/unit/src/UserMembership/UserMembershipsHandler.test.mjs b/services/web/test/unit/src/UserMembership/UserMembershipsHandler.test.mjs
index 7885d1fa8f..d06510fc44 100644
--- a/services/web/test/unit/src/UserMembership/UserMembershipsHandler.test.mjs
+++ b/services/web/test/unit/src/UserMembership/UserMembershipsHandler.test.mjs
@@ -17,15 +17,15 @@ describe('UserMembershipsHandler', function () {
     ctx.Publisher = { updateMany: sinon.stub().resolves(null) }
 
     vi.doMock('../../../../app/src/models/Institution', () => ({
-      Institution: ctx.Institution,
+      default: { Institution: ctx.Institution },
     }))
 
     vi.doMock('../../../../app/src/models/Subscription', () => ({
-      Subscription: ctx.Subscription,
+      default: { Subscription: ctx.Subscription },
     }))
 
     vi.doMock('../../../../app/src/models/Publisher', () => ({
-      Publisher: ctx.Publisher,
+      default: { Publisher: ctx.Publisher },
     }))
 
     ctx.UserMembershipsHandler = (await import(modulePath)).default
diff --git a/services/web/test/unit/src/helpers/MockModel.js b/services/web/test/unit/src/helpers/MockModel.js
new file mode 100644
index 0000000000..764dd5240a
--- /dev/null
+++ b/services/web/test/unit/src/helpers/MockModel.js
@@ -0,0 +1,39 @@
+const SandboxedModule = require('sandboxed-module')
+const mongoose = require('mongoose')
+
+/**
+ * Imports a model as we would usually do with e.g. `require('models/User')`
+ * an returns a model an schema, but without connecting to Mongo. This allows
+ * us to use model classes in tests, and to use them with `sinon-mongoose`
+ *
+ * @param  modelName the name of the model - e.g. 'User'
+ * @param  requires  additional `requires` to be passed to SanboxedModule in
+ *                   the event that these also need to be stubbed. For example,
+ *                   additional dependent models to be included
+ *
+ * @return model and schema pair - e.g. { User, UserSchema }
+ */
+
+module.exports = (modelName, requires = {}) => {
+  const model = {}
+
+  requires['../infrastructure/Mongoose'] = {
+    createConnection: () => {
+      return {
+        model: () => {},
+      }
+    },
+    model: (modelName, schema) => {
+      model[modelName + 'Schema'] = schema
+      model[modelName] = mongoose.model(modelName, schema)
+    },
+    Schema: mongoose.Schema,
+    Types: mongoose.Types,
+  }
+
+  SandboxedModule.require('../../../../app/src/models/' + modelName, {
+    requires,
+  })
+
+  return model
+}
diff --git a/services/web/test/unit/src/helpers/indirectlyImportModels.js b/services/web/test/unit/src/helpers/indirectlyImportModels.js
new file mode 100644
index 0000000000..cfa4706b49
--- /dev/null
+++ b/services/web/test/unit/src/helpers/indirectlyImportModels.js
@@ -0,0 +1,19 @@
+// When importing models in vitest unit tests we need to import them from a CJS file
+// instead of directly from the test file so that we can mock the model when it is imported via CJS
+// and make sure that is in the require cache for other imports.
+//
+// TODO: This helper can be removed when all models are converted to ESM and vitest can handle them correctly.
+
+/**
+ *
+ * @param {string[]} models
+ */
+module.exports = function (models) {
+  return models.reduce((exports, model) => {
+    const module = require(`./models/${model}`)
+    return {
+      ...exports,
+      ...module,
+    }
+  }, {})
+}
diff --git a/services/web/test/unit/src/helpers/models/DeletedProject.js b/services/web/test/unit/src/helpers/models/DeletedProject.js
new file mode 100644
index 0000000000..f3537bcb43
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/DeletedProject.js
@@ -0,0 +1,5 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('DeletedProject', {
+  './Project': require('./Project'),
+})
diff --git a/services/web/test/unit/src/helpers/models/DeletedUser.js b/services/web/test/unit/src/helpers/models/DeletedUser.js
new file mode 100644
index 0000000000..92d932c784
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/DeletedUser.js
@@ -0,0 +1,5 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('DeletedUser', {
+  './User': require('./User'),
+})
diff --git a/services/web/test/unit/src/helpers/models/Doc.js b/services/web/test/unit/src/helpers/models/Doc.js
new file mode 100644
index 0000000000..ac7bed3683
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/Doc.js
@@ -0,0 +1,3 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('Doc')
diff --git a/services/web/test/unit/src/helpers/models/File.js b/services/web/test/unit/src/helpers/models/File.js
new file mode 100644
index 0000000000..3c57aa363e
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/File.js
@@ -0,0 +1,3 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('File')
diff --git a/services/web/test/unit/src/helpers/models/Folder.js b/services/web/test/unit/src/helpers/models/Folder.js
new file mode 100644
index 0000000000..3abf588ff9
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/Folder.js
@@ -0,0 +1,6 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('Folder', {
+  './Doc': require('./Doc'),
+  './File': require('./File'),
+})
diff --git a/services/web/test/unit/src/helpers/models/Project.js b/services/web/test/unit/src/helpers/models/Project.js
new file mode 100644
index 0000000000..508db37d85
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/Project.js
@@ -0,0 +1,5 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('Project', {
+  './Folder': require('./Folder'),
+})
diff --git a/services/web/test/unit/src/helpers/models/Tag.js b/services/web/test/unit/src/helpers/models/Tag.js
new file mode 100644
index 0000000000..fa6c2aa1f5
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/Tag.js
@@ -0,0 +1,3 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('Tag')
diff --git a/services/web/test/unit/src/helpers/models/User.js b/services/web/test/unit/src/helpers/models/User.js
new file mode 100644
index 0000000000..7190fd6640
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/User.js
@@ -0,0 +1,5 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('User', {
+  './Project': require('./Project'),
+})
diff --git a/services/web/test/unit/src/helpers/models/UserAuditLogEntry.js b/services/web/test/unit/src/helpers/models/UserAuditLogEntry.js
new file mode 100644
index 0000000000..f31838ba3d
--- /dev/null
+++ b/services/web/test/unit/src/helpers/models/UserAuditLogEntry.js
@@ -0,0 +1,3 @@
+const mockModel = require('../MockModel')
+
+module.exports = mockModel('UserAuditLogEntry')
diff --git a/services/web/test/unit/src/infrastructure/Mongodb.test.mjs b/services/web/test/unit/src/infrastructure/MongodbTests.js
similarity index 98%
rename from services/web/test/unit/src/infrastructure/Mongodb.test.mjs
rename to services/web/test/unit/src/infrastructure/MongodbTests.js
index 28ae2c6171..65cab5f7b6 100644
--- a/services/web/test/unit/src/infrastructure/Mongodb.test.mjs
+++ b/services/web/test/unit/src/infrastructure/MongodbTests.js
@@ -1,8 +1,6 @@
-import mongodb from 'mongodb-legacy'
-import { expect } from 'vitest'
-import sinon from 'sinon'
-
-const { ObjectId } = mongodb
+const { ObjectId } = require('mongodb-legacy')
+const { expect } = require('chai')
+const sinon = require('sinon')
 
 describe('Mongo ObjectId comparison', function () {
   const ObjectId1 = new ObjectId('111111111111111111111111')
diff --git a/services/web/test/unit/vitest_bootstrap.mjs b/services/web/test/unit/vitest_bootstrap.mjs
index cc057bd1f0..50ff559bc9 100644
--- a/services/web/test/unit/vitest_bootstrap.mjs
+++ b/services/web/test/unit/vitest_bootstrap.mjs
@@ -4,7 +4,35 @@ import sinon from 'sinon'
 import logger from '@overleaf/logger'
 import sinonChai from 'sinon-chai'
 import chaiAsPromised from 'chai-as-promised'
-import mongoose from 'mongoose'
+import SandboxedModule from 'sandboxed-module'
+import { createRequire } from 'module'
+
+const require = createRequire(import.meta.url)
+
+SandboxedModule.configure({
+  ignoreMissing: true,
+  requires: {
+    // This is already imported the same way in the mocha bootstrap
+    // eslint-disable-next-line import/no-extraneous-dependencies
+    sshpk: require('sshpk'),
+  },
+  globals: {
+    AbortController,
+    AbortSignal,
+    Buffer,
+    Promise,
+    console,
+    process,
+    URL,
+    TextEncoder,
+    TextDecoder,
+  },
+  sourceTransformers: {
+    removeNodePrefix: function (source) {
+      return source.replace(/require\(['"]node:/g, "require('")
+    },
+  },
+})
 
 /*
  * Chai configuration
@@ -52,8 +80,4 @@ afterEach(() => {
   vi.restoreAllMocks()
   vi.resetModules()
   sinon.restore()
-  const modelNames = mongoose.modelNames()
-  modelNames.forEach(name => {
-    delete mongoose.connection.models[name]
-  })
 })