diff --git a/libraries/eslint-plugin/index.js b/libraries/eslint-plugin/index.js
index 10598abe45..5e6175a095 100644
--- a/libraries/eslint-plugin/index.js
+++ b/libraries/eslint-plugin/index.js
@@ -7,5 +7,6 @@ module.exports = {
     'require-script-runner': require('./require-script-runner'),
     'require-vi-doMock-valid-path': require('./require-vi-doMock-valid-path'),
     'require-loading-label': require('./require-loading-label'),
+    'require-cio-snake-case-properties': require('./require-cio-snake-case-properties'),
   },
 }
diff --git a/libraries/eslint-plugin/require-cio-snake-case-properties.js b/libraries/eslint-plugin/require-cio-snake-case-properties.js
new file mode 100644
index 0000000000..a17d25e7b4
--- /dev/null
+++ b/libraries/eslint-plugin/require-cio-snake-case-properties.js
@@ -0,0 +1,111 @@
+'use strict'
+
+const SNAKE_CASE_RE = /^[a-z][a-z0-9]*(_[a-z0-9]+)*$/
+
+function isSnakeCase(name) {
+  return SNAKE_CASE_RE.test(name)
+}
+
+function getStaticKeyName(property) {
+  if (property.computed) return null
+  if (property.key.type === 'Identifier') return property.key.name
+  if (property.key.type === 'Literal' && typeof property.key.value === 'string')
+    return property.key.value
+  return null
+}
+
+/**
+ * Check if a node is a call to CustomerIoHandler.updateUserAttributes()
+ * and return the attributes argument (2nd argument)
+ */
+function getUpdateUserAttributesArg(node) {
+  if (
+    node.callee.type === 'MemberExpression' &&
+    node.callee.object.type === 'Identifier' &&
+    node.callee.object.name === 'CustomerIoHandler' &&
+    node.callee.property.name === 'updateUserAttributes' &&
+    node.arguments[1]?.type === 'ObjectExpression'
+  ) {
+    return node.arguments[1]
+  }
+  return null
+}
+
+/**
+ * Check if a node is a call to Modules[.promises].hooks.fire('setUserProperties', ...)
+ * and return the attributes argument (3rd argument)
+ */
+function getSetUserPropertiesArg(node) {
+  const callee = node.callee
+  if (callee.type !== 'MemberExpression' || callee.property.name !== 'fire') {
+    return null
+  }
+
+  // Check first argument is 'setUserProperties'
+  if (
+    !node.arguments[0] ||
+    node.arguments[0].type !== 'Literal' ||
+    node.arguments[0].value !== 'setUserProperties'
+  ) {
+    return null
+  }
+
+  // Match: Modules.hooks.fire or Modules.promises.hooks.fire
+  const obj = callee.object
+  if (obj.type === 'MemberExpression' && obj.property.name === 'hooks') {
+    const parent = obj.object
+    // Modules.hooks
+    if (parent.type === 'Identifier' && parent.name === 'Modules') {
+      if (node.arguments[2]?.type === 'ObjectExpression') {
+        return node.arguments[2]
+      }
+    }
+    // Modules.promises.hooks
+    if (
+      parent.type === 'MemberExpression' &&
+      parent.property.name === 'promises' &&
+      parent.object.type === 'Identifier' &&
+      parent.object.name === 'Modules'
+    ) {
+      if (node.arguments[2]?.type === 'ObjectExpression') {
+        return node.arguments[2]
+      }
+    }
+  }
+
+  return null
+}
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description:
+        'Enforce snake_case for Customer.io user property attribute names',
+    },
+  },
+  create(context) {
+    return {
+      CallExpression(node) {
+        const attrsNode =
+          getUpdateUserAttributesArg(node) || getSetUserPropertiesArg(node)
+        if (!attrsNode) return
+
+        for (const property of attrsNode.properties) {
+          if (property.type === 'SpreadElement') continue
+
+          const keyName = getStaticKeyName(property)
+          if (keyName === null) continue // skip computed/dynamic keys
+
+          if (!isSnakeCase(keyName)) {
+            context.report({
+              node: property.key,
+              message: `Customer.io attribute '{{name}}' must be in snake_case.`,
+              data: { name: keyName },
+            })
+          }
+        }
+      },
+    }
+  },
+}
diff --git a/libraries/eslint-plugin/rules.test.js b/libraries/eslint-plugin/rules.test.js
index f7f85f9016..377ba0316c 100644
--- a/libraries/eslint-plugin/rules.test.js
+++ b/libraries/eslint-plugin/rules.test.js
@@ -4,6 +4,7 @@ const noUnnecessaryTrans = require('./no-unnecessary-trans')
 const shouldUnescapeTrans = require('./should-unescape-trans')
 const noGeneratedEditorThemes = require('./no-generated-editor-themes')
 const viDoMockValidPath = require('./require-vi-doMock-valid-path')
+const requireCioSnakeCaseProperties = require('./require-cio-snake-case-properties')
 
 const ruleTester = new RuleTester({
   parser: require.resolve('@typescript-eslint/parser'),
@@ -166,3 +167,103 @@ ruleTester.run('domock-require-valid-path', viDoMockValidPath, {
     },
   ],
 })
+
+ruleTester.run(
+  'require-cio-snake-case-properties',
+  requireCioSnakeCaseProperties,
+  {
+    valid: [
+      // updateUserAttributes with snake_case keys
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { plan_type: 'free', group_size: 10 })`,
+      },
+      // Modules.promises.hooks.fire with snake_case keys
+      {
+        code: `Modules.promises.hooks.fire('setUserProperties', userId, { plan_type: 'free', last_active: 123 })`,
+      },
+      // Modules.hooks.fire with snake_case keys
+      {
+        code: `Modules.hooks.fire('setUserProperties', userId, { plan_type: 'free' })`,
+      },
+      // Single-word keys are valid snake_case
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { email: 'a@b.com', role: 'admin' })`,
+      },
+      // Computed/dynamic keys are skipped
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { [dynamicKey]: true })`,
+      },
+      // Spread elements are skipped
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { ...existingAttrs })`,
+      },
+      // Unrelated function calls are not checked
+      {
+        code: `SomeOtherHandler.updateUserAttributes(userId, { camelCase: true })`,
+      },
+      // fire() with a different event name is not checked
+      {
+        code: `Modules.promises.hooks.fire('someOtherEvent', userId, { camelCase: true })`,
+      },
+    ],
+    invalid: [
+      // camelCase key in updateUserAttributes
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { planType: 'free' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'planType' must be in snake_case.`,
+          },
+        ],
+      },
+      // kebab-case string key
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { 'plan-type': 'free' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'plan-type' must be in snake_case.`,
+          },
+        ],
+      },
+      // PascalCase key
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { PlanType: 'free' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'PlanType' must be in snake_case.`,
+          },
+        ],
+      },
+      // camelCase in Modules.promises.hooks.fire
+      {
+        code: `Modules.promises.hooks.fire('setUserProperties', userId, { planType: 'free' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'planType' must be in snake_case.`,
+          },
+        ],
+      },
+      // camelCase in Modules.hooks.fire
+      {
+        code: `Modules.hooks.fire('setUserProperties', userId, { planType: 'free' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'planType' must be in snake_case.`,
+          },
+        ],
+      },
+      // Multiple invalid keys report multiple errors
+      {
+        code: `CustomerIoHandler.updateUserAttributes(userId, { planType: 'free', groupSize: 10, plan_term: 'annual' })`,
+        errors: [
+          {
+            message: `Customer.io attribute 'planType' must be in snake_case.`,
+          },
+          {
+            message: `Customer.io attribute 'groupSize' must be in snake_case.`,
+          },
+        ],
+      },
+    ],
+  }
+)
diff --git a/services/web/.eslintrc.js b/services/web/.eslintrc.js
index 0a45fde7a8..3a9b106394 100644
--- a/services/web/.eslintrc.js
+++ b/services/web/.eslintrc.js
@@ -29,6 +29,7 @@ module.exports = {
     'import/no-extraneous-dependencies': 'error',
 
     '@overleaf/prefer-kebab-url': 'error',
+    '@overleaf/require-cio-snake-case-properties': 'error',
 
     // disable some TypeScript rules
     '@typescript-eslint/no-var-requires': 'off',
diff --git a/services/web/app/src/Features/Project/ProjectListController.mjs b/services/web/app/src/Features/Project/ProjectListController.mjs
index 4a38ecc4f2..e00059ff12 100644
--- a/services/web/app/src/Features/Project/ProjectListController.mjs
+++ b/services/web/app/src/Features/Project/ProjectListController.mjs
@@ -34,7 +34,7 @@ import { OnboardingDataCollection } from '../../models/OnboardingDataCollection.
 import UserSettingsHelper from './UserSettingsHelper.mjs'
 
 /**
- * @import { GetProjectsRequest, GetProjectsResponse, AllUsersProjects, MongoProject, FormattedProject, MongoTag } from "./types"
+ * @import { GetProjectsRequest, GetProjectsResponse, AllUsersProjects, MongoProject, FormattedProject, MongoTag, SubscriptionRecord } from "./types"
  * @import { Project, ProjectApi, ProjectAccessLevel, Filters, Page, Sort, UserRef } from "../../../../types/project/dashboard/api"
  * @import { Affiliation } from "../../../../types/affiliation"
  * @import { Source } from "../Authorization/types"
@@ -554,26 +554,26 @@ async function projectListPage(req, res, next) {
 
   Modules.promises.hooks
     .fire('setUserProperties', userId, {
-      overleafId: userId,
-      lastActive: user.lastActive
+      overleaf_id: userId,
+      last_active: user.lastActive
         ? Math.floor(user.lastActive.getTime() / 1000)
         : null,
-      signUpDate: user.signUpDate
+      sign_up_date: user.signUpDate
         ? Math.floor(user.signUpDate.getTime() / 1000)
         : null,
       ...(usersBestSubscription?.type && {
-        'best-subscription-type': usersBestSubscription.type,
+        best_subscription_type: usersBestSubscription.type,
       }),
-      aiBlocked,
-      hasAiAssist,
-      ...(subjectArea && { subjectArea }),
+      ai_blocked: aiBlocked,
+      has_ai_assist: hasAiAssist,
+      ...(subjectArea && { subject_area: subjectArea }),
       ...(role && { role }),
-      ...(primaryOccupation && { primaryOccupation }),
-      ...(usedLatex && { usedLatex }),
+      ...(primaryOccupation && { primary_occupation: primaryOccupation }),
+      ...(usedLatex && { used_latex: usedLatex }),
       ...(countryCode && { country: countryCode }),
-      ...(commonsInstitution && { commonsInstitution }),
-      ...(groupRole && { groupRole }),
-      isManagedUser: Boolean(user.enrollment?.managedBy),
+      ...(commonsInstitution && { commons_institution: commonsInstitution }),
+      ...(groupRole && { group_role: groupRole }),
+      is_managed_user: Boolean(user.enrollment?.managedBy),
       ...(user.email && { email: user.email }),
     })
     .catch(err => {
diff --git a/services/web/app/src/Features/Subscription/CustomerIoPlanHelpers.mjs b/services/web/app/src/Features/Subscription/CustomerIoPlanHelpers.mjs
new file mode 100644
index 0000000000..e1071bd9b2
--- /dev/null
+++ b/services/web/app/src/Features/Subscription/CustomerIoPlanHelpers.mjs
@@ -0,0 +1,408 @@
+import Settings from '@overleaf/settings'
+import { AI_ADD_ON_CODE, isStandaloneAiAddOnPlanCode } from './AiHelper.mjs'
+import FeaturesHelper from './FeaturesHelper.mjs'
+
+const INACTIVE_NEXT_RENEWAL_DATE_STATES = new Set([
+  'canceled',
+  'cancelled',
+  'expired',
+])
+const PENDING_CANCELLATION_STATES = new Set(['canceled', 'cancelled'])
+
+function getSubscriptionState(subscription) {
+  return (
+    subscription?.recurlyStatus?.state || subscription?.paymentProvider?.state
+  )
+}
+
+function toUnixTimestamp(dateValue) {
+  if (!dateValue) {
+    return null
+  }
+
+  const date = new Date(dateValue)
+  if (Number.isNaN(date.getTime())) {
+    return null
+  }
+
+  return Math.floor(date.getTime() / 1000)
+}
+
+function normalizePlanType(bestSubscription) {
+  if (!bestSubscription) {
+    return null
+  }
+
+  if (['standalone-ai-add-on', 'commons'].includes(bestSubscription.type)) {
+    return bestSubscription.type
+  }
+
+  const planCode = bestSubscription.plan?.planCode
+  const isGroupPlan = bestSubscription.plan?.groupPlan === true
+
+  if (!planCode) {
+    return bestSubscription.type || null
+  }
+
+  if (planCode.startsWith('v1_')) {
+    return 'v1'
+  }
+
+  if (planCode.includes('student')) {
+    return 'student'
+  }
+
+  if (planCode.includes('professional')) {
+    return isGroupPlan ? 'group-professional' : 'professional'
+  }
+
+  if (planCode.includes('collaborator')) {
+    return isGroupPlan ? 'group-standard' : 'standard'
+  }
+
+  if (planCode.includes('personal')) {
+    return 'personal'
+  }
+
+  if (isGroupPlan) {
+    return 'group-standard'
+  }
+
+  return planCode
+}
+
+function getFriendlyPlanName(planType) {
+  if (!planType) {
+    return null
+  }
+
+  const friendlyPlanNames = {
+    free: 'Free',
+    personal: 'Personal',
+    standard: 'Standard',
+    professional: 'Pro',
+    student: 'Student',
+    commons: 'Commons',
+    'group-standard': 'Group Standard',
+    'group-professional': 'Group Pro',
+    'standalone-ai-add-on': 'AI Assist add-on',
+    v1: 'Legacy',
+  }
+
+  if (friendlyPlanNames[planType]) {
+    return friendlyPlanNames[planType]
+  }
+
+  return planType
+}
+
+function getPlanCadence(bestSubscription) {
+  if (!bestSubscription?.plan) {
+    return null
+  }
+
+  return bestSubscription.plan.annual ? 'annual' : 'monthly'
+}
+
+function getPlanCadenceFromPlanCode(planCode) {
+  if (!planCode) {
+    return null
+  }
+
+  const plan = Settings.plans.find(candidate => candidate.planCode === planCode)
+  if (plan) {
+    return plan.annual ? 'annual' : 'monthly'
+  }
+
+  if (planCode.includes('annual')) {
+    return 'annual'
+  }
+
+  if (isStandaloneAiAddOnPlanCode(planCode)) {
+    return 'monthly'
+  }
+
+  return null
+}
+
+function getNextRenewalDateFromPaymentRecord(paymentRecord) {
+  const subscriptionState = paymentRecord?.subscription?.state
+  if (INACTIVE_NEXT_RENEWAL_DATE_STATES.has(subscriptionState)) {
+    return null
+  }
+
+  return toUnixTimestamp(paymentRecord?.subscription?.periodEnd)
+}
+
+function shouldClearNextRenewalDate(subscription) {
+  if (!subscription) {
+    return true
+  }
+
+  return INACTIVE_NEXT_RENEWAL_DATE_STATES.has(
+    getSubscriptionState(subscription)
+  )
+}
+
+function getExpiryDateFromPaymentRecord(paymentRecord) {
+  const subscriptionState = paymentRecord?.subscription?.state
+  if (!PENDING_CANCELLATION_STATES.has(subscriptionState)) {
+    return null
+  }
+
+  const expiryDate = toUnixTimestamp(paymentRecord?.subscription?.periodEnd)
+  if (expiryDate == null) {
+    return null
+  }
+
+  return expiryDate > Math.floor(Date.now() / 1000) ? expiryDate : null
+}
+
+function shouldClearExpiryDate(subscription) {
+  if (!subscription) {
+    return true
+  }
+
+  return !PENDING_CANCELLATION_STATES.has(getSubscriptionState(subscription))
+}
+
+function hasIndividualAiAssistAddOn(individualSubscription, paymentRecord) {
+  if (
+    !individualSubscription ||
+    individualSubscription.groupPlan ||
+    isStandaloneAiAddOnPlanCode(individualSubscription.planCode)
+  ) {
+    return false
+  }
+
+  return Boolean(
+    paymentRecord?.subscription?.addOns?.some(
+      addOn => addOn.code === AI_ADD_ON_CODE
+    )
+  )
+}
+
+function getAiPlanType(
+  bestSubscription,
+  individualSubscription,
+  paymentRecord,
+  writefullData
+) {
+  if (
+    bestSubscription?.type === 'standalone-ai-add-on' ||
+    isStandaloneAiAddOnPlanCode(individualSubscription?.planCode)
+  ) {
+    return 'ai-assist-standalone'
+  }
+
+  if (hasIndividualAiAssistAddOn(individualSubscription, paymentRecord)) {
+    return 'ai-assist-add-on'
+  }
+
+  if (writefullData?.isPremium) {
+    return 'writefull-premium'
+  }
+
+  return 'none'
+}
+
+function getAiPlanCadence(
+  aiPlan,
+  bestSubscription,
+  individualSubscription,
+  paymentRecord
+) {
+  if (aiPlan === 'ai-assist-standalone') {
+    return (
+      getPlanCadenceFromPlanCode(individualSubscription?.planCode) ||
+      getPlanCadenceFromPlanCode(paymentRecord?.subscription?.planCode)
+    )
+  }
+
+  if (aiPlan === 'ai-assist-add-on') {
+    return (
+      getPlanCadence(bestSubscription) ||
+      getPlanCadenceFromPlanCode(individualSubscription?.planCode)
+    )
+  }
+
+  return null
+}
+
+function hasPlanAiEnabled(plan) {
+  if (!plan?.features) {
+    return false
+  }
+
+  return (
+    plan.features.aiUsageQuota === Settings.aiFeatures.unlimitedQuota ||
+    plan.features.aiErrorAssistant === true
+  )
+}
+
+function getGroupAiEnabled(
+  memberGroupSubscriptions = [],
+  managedGroupSubscriptions = [],
+  userIsMemberOfGroupSubscription
+) {
+  if (!userIsMemberOfGroupSubscription) {
+    return null
+  }
+
+  const allGroupSubscriptions = [
+    ...memberGroupSubscriptions,
+    ...managedGroupSubscriptions,
+  ]
+
+  return allGroupSubscriptions.some(subscription => {
+    const plan = Settings.plans.find(
+      candidate => candidate.planCode === subscription.planCode
+    )
+    return hasPlanAiEnabled(plan)
+  })
+}
+
+function getGroupSize(
+  bestSubscription,
+  memberGroupSubscriptions = [],
+  managedGroupSubscriptions = []
+) {
+  const allGroupSubscriptions = [
+    ...memberGroupSubscriptions,
+    ...managedGroupSubscriptions,
+  ]
+
+  if (allGroupSubscriptions.length === 0) {
+    return null
+  }
+
+  const matchingBestGroupSubscription =
+    bestSubscription?.type === 'group'
+      ? allGroupSubscriptions.find(
+          subscription =>
+            subscription.planCode === bestSubscription.plan?.planCode &&
+            subscription.teamName === bestSubscription.subscription?.teamName
+        )
+      : null
+
+  if (matchingBestGroupSubscription?.membersLimit != null) {
+    return matchingBestGroupSubscription.membersLimit
+  }
+
+  if (bestSubscription?.subscription?.membersLimit != null) {
+    return bestSubscription.subscription.membersLimit
+  }
+
+  if (
+    bestSubscription?.plan?.groupPlan &&
+    bestSubscription.plan.membersLimit != null
+  ) {
+    return bestSubscription.plan.membersLimit
+  }
+
+  return allGroupSubscriptions.reduce((largestGroupSize, subscription) => {
+    const plan = Settings.plans.find(
+      candidate => candidate.planCode === subscription.planCode
+    )
+    const groupSize = subscription.membersLimit ?? plan?.membersLimit ?? 0
+
+    return Math.max(largestGroupSize, groupSize)
+  }, 0)
+}
+
+function shouldUseCommonsBestSubscription(
+  hasCommons,
+  bestSubscription,
+  commonsPlan
+) {
+  if (!hasCommons) {
+    return false
+  }
+
+  if (bestSubscription == null) {
+    return true
+  }
+
+  return FeaturesHelper.isFeatureSetBetter(
+    commonsPlan?.features || {},
+    bestSubscription.plan?.features || {}
+  )
+}
+
+/**
+ * Compute plan-related user properties for sending to customer.io.
+ */
+function getPlanProperties({
+  bestSubscription,
+  individualSubscription,
+  individualPaymentRecord,
+  memberGroupSubscriptions,
+  managedGroupSubscriptions,
+  userIsMemberOfGroupSubscription,
+  writefullData,
+}) {
+  const planType = normalizePlanType(bestSubscription)
+  const displayPlanType = getFriendlyPlanName(planType)
+  const planTermLabel = getPlanCadence(bestSubscription)
+  const aiPlan = getAiPlanType(
+    bestSubscription,
+    individualSubscription,
+    individualPaymentRecord,
+    writefullData
+  )
+  const aiPlanTermLabel = getAiPlanCadence(
+    aiPlan,
+    bestSubscription,
+    individualSubscription,
+    individualPaymentRecord
+  )
+  const groupAiEnabled = getGroupAiEnabled(
+    memberGroupSubscriptions,
+    managedGroupSubscriptions,
+    userIsMemberOfGroupSubscription
+  )
+  const nextRenewalDate = getNextRenewalDateFromPaymentRecord(
+    individualPaymentRecord
+  )
+  const expiryDate = getExpiryDateFromPaymentRecord(individualPaymentRecord)
+  const groupSizeValue = getGroupSize(
+    bestSubscription,
+    memberGroupSubscriptions,
+    managedGroupSubscriptions
+  )
+
+  const nextRenewalDateTrait =
+    nextRenewalDate ??
+    (shouldClearNextRenewalDate(individualSubscription) ? '' : undefined)
+  const expiryDateTrait =
+    expiryDate ??
+    (shouldClearExpiryDate(individualSubscription) ? '' : undefined)
+
+  const properties = {
+    ai_plan: aiPlan,
+  }
+
+  if (planType) properties.plan_type = planType
+  if (displayPlanType) properties.display_plan_type = displayPlanType
+  if (planTermLabel) properties.plan_term_label = planTermLabel
+  if (aiPlanTermLabel) properties.ai_plan_term_label = aiPlanTermLabel
+  if (groupAiEnabled !== null) properties.group_ai_enabled = groupAiEnabled
+  if (nextRenewalDateTrait !== undefined)
+    properties.next_renewal_date = nextRenewalDateTrait
+  if (expiryDateTrait !== undefined) properties.expiry_date = expiryDateTrait
+  if (groupSizeValue !== null) properties.group_size = groupSizeValue
+
+  return properties
+}
+
+export default {
+  normalizePlanType,
+  getFriendlyPlanName,
+  getNextRenewalDateFromPaymentRecord,
+  getExpiryDateFromPaymentRecord,
+  getAiPlanType,
+  getAiPlanCadence,
+  hasPlanAiEnabled,
+  shouldUseCommonsBestSubscription,
+  getPlanProperties,
+}
diff --git a/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs b/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
index 61dbb23ce8..1e400b0f24 100644
--- a/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
+++ b/services/web/app/src/Features/Subscription/FeaturesUpdater.mjs
@@ -16,6 +16,7 @@ import AnalyticsManager from '../Analytics/AnalyticsManager.mjs'
 import Queues from '../../infrastructure/Queues.mjs'
 import Modules from '../../infrastructure/Modules.mjs'
 import SubscriptionViewModelBuilder from './SubscriptionViewModelBuilder.mjs'
+import CustomerIoPlanHelpers from './CustomerIoPlanHelpers.mjs'
 import { AI_ADD_ON_CODE } from './AiHelper.mjs'
 import { fetchNothing } from '@overleaf/fetch-utils'
 import SplitTestHandler from '../SplitTests/SplitTestHandler.mjs'
@@ -58,18 +59,12 @@ async function refreshFeatures(userId, reason) {
   const { features: newFeatures, featuresChanged } =
     await UserFeaturesUpdater.promises.updateFeatures(userId, features)
 
-  const bestSubscriptionType = await _getBestSubscriptionType(userId)
-
-  Modules.promises.hooks
-    .fire('setUserProperties', userId, {
-      features,
-      'best-subscription-type': bestSubscriptionType,
-      overleafId: userId,
-      ...(user.email && { email: user.email }),
-    })
-    .catch(err => {
-      logger.error({ err, userId }, 'Failed to sync features to customer.io')
-    })
+  _updateCustomerIoSubscriptionProperties(user, features).catch(err => {
+    logger.warn(
+      { err, userId },
+      'Failed to update subscription properties in customer.io'
+    )
+  })
 
   if (oldFeatures.dropbox === true && features.dropbox === false) {
     logger.debug({ userId }, '[FeaturesUpdater] must unlink dropbox')
@@ -133,20 +128,61 @@ async function refreshFeatures(userId, reason) {
   return { features: newFeatures, featuresChanged }
 }
 
-async function _getBestSubscriptionType(userId) {
-  try {
-    const { bestSubscription } =
-      await SubscriptionViewModelBuilder.promises.getUsersSubscriptionDetails({
-        _id: userId,
-      })
-    return bestSubscription?.type || 'free'
-  } catch (err) {
-    logger.warn(
-      { err, userId },
-      'Failed to calculate best-subscription-type for customer.io'
-    )
-    return 'free'
+async function _updateCustomerIoSubscriptionProperties(user, features) {
+  const userId = user._id
+  const {
+    bestSubscription,
+    individualSubscription,
+    memberGroupSubscriptions,
+    managedGroupSubscriptions,
+  } = await SubscriptionViewModelBuilder.promises.getUsersSubscriptionDetails({
+    _id: userId,
+  })
+
+  const userIsMemberOfGroupSubscription =
+    memberGroupSubscriptions.length > 0 || managedGroupSubscriptions.length > 0
+
+  let individualPaymentRecord = null
+  if (individualSubscription && !individualSubscription.groupPlan) {
+    try {
+      ;[individualPaymentRecord] = await Modules.promises.hooks.fire(
+        'getPaymentFromRecordPromise',
+        individualSubscription
+      )
+    } catch (error) {
+      logger.warn(
+        { err: error, userId },
+        'Failed to load payment record for customer.io subscription properties'
+      )
+    }
   }
+
+  let writefullData = null
+  try {
+    writefullData = await UserGetter.promises.getWritefullData(userId)
+  } catch (error) {
+    logger.warn(
+      { err: error, userId },
+      'Failed to load writefull data for customer.io subscription properties'
+    )
+  }
+
+  const planProperties = CustomerIoPlanHelpers.getPlanProperties({
+    bestSubscription,
+    individualSubscription,
+    individualPaymentRecord,
+    memberGroupSubscriptions,
+    managedGroupSubscriptions,
+    userIsMemberOfGroupSubscription,
+    writefullData,
+  })
+
+  await Modules.promises.hooks.fire('setUserProperties', userId, {
+    ...planProperties,
+    features,
+    overleaf_id: userId,
+    ...(user.email && { email: user.email }),
+  })
 }
 
 /**
diff --git a/services/web/scripts/batch_identify_to_cio.mjs b/services/web/scripts/batch_identify_to_cio.mjs
new file mode 100644
index 0000000000..0de7971d8f
--- /dev/null
+++ b/services/web/scripts/batch_identify_to_cio.mjs
@@ -0,0 +1,465 @@
+#!/usr/bin/env node
+
+/**
+ * This script reads a CSV file (output from migrate_mailchimp_to_cio.mjs or
+ * export_active_subscription_users_csv.mjs) and
+ * makes batch identify requests to Customer.io using the CDP Analytics node library.
+ *
+ * Usage:
+ *   node scripts/batch_identify_to_cio.mjs --input INPUT-FILE [OPTIONS]
+ *
+ * Example:
+ *   node scripts/batch_identify_to_cio.mjs --input /tmp/customerio_import.csv
+ *   CUSTOMER_IO_API_KEY=xxx node scripts/batch_identify_to_cio.mjs --input /tmp/customerio_import.csv --commit
+ *
+ * Resuming after failure:
+ *   CUSTOMER_IO_API_KEY=xxx node scripts/batch_identify_to_cio.mjs --input /tmp/customerio_import.csv --commit --skip 50000
+ *
+ * Options:
+ *   --input, -i PATH       Input CSV file (from migrate_mailchimp_to_cio.mjs) (required)
+ *   --commit               Actually send to Customer.io (default is dry-run)
+ *   --skip N               Skip the first N rows (for resuming after failure)
+ *   --batch-size N         Maximum items per batch (default: 1000)
+ *   --help, -h             Show this help message
+ *
+ * Environment Variables:
+ *   CUSTOMER_IO_API_KEY    Customer.io CDP API key (required when using --commit)
+ *
+ * CSV Input Format (from migrate_mailchimp_to_cio.mjs):
+ *   - email: Subscriber email address
+ *   - overleafId: Overleaf user ID (from mongo_id)
+ *   - created_at: Unix timestamp
+ *   - cio_subscription_preferences.topics.<topic_id>: 'true' if subscribed
+ *   - labsExperiments: JSON array of experiment names
+ *
+ * CSV Input Format (from export_active_subscription_users_csv.mjs):
+ *   - user_id: Overleaf user ID
+ *   - email: Subscriber email address
+ *   - plan_type, display_plan_type, pre_migration_plan_type,
+ *     pre_migration_display_plan_type, plan_term, ai_plan, ai_plan_term,
+ *     next_renewal_date, expiry_date, group_ai_enabled, group_role
+ *
+ * Rate Limiting:
+ *   - Max 3000 requests per 3 seconds (Customer.io limit)
+ *   - Progress is logged every 10000 rows for recovery purposes
+ *
+ * Notes:
+ *   - Users are identified by email address (used as userId)
+ *   - The library handles batching internally via maxEventsInBatch
+ */
+
+import fs, { createReadStream } from 'node:fs'
+import * as csv from 'csv'
+import minimist from 'minimist'
+import { Analytics } from '@customerio/cdp-analytics-node'
+import { scriptRunner } from './lib/ScriptRunner.mjs'
+
+const DEFAULT_BATCH_SIZE = 1000
+const RATE_LIMIT_REQUESTS = 3000
+const RATE_LIMIT_WINDOW_MS = 3000
+const PROGRESS_LOG_INTERVAL = 10000
+
+function usage() {
+  console.error(`Usage: node scripts/batch_identify_to_cio.mjs --input INPUT-FILE [OPTIONS]
+
+Options:
+    --input, -i PATH       Input CSV file (from migrate_mailchimp_to_cio.mjs) (required)
+    --commit               Actually send to Customer.io (default is dry-run)
+    --skip N               Skip the first N rows (for resuming after failure)
+    --batch-size N         Maximum items per batch (default: ${DEFAULT_BATCH_SIZE})
+    --help, -h             Show this help message
+
+Environment Variables:
+    CUSTOMER_IO_API_KEY    Customer.io CDP API key (required when using --commit)
+`)
+  process.exit(1)
+}
+
+/**
+ * Simple rate limiter that enforces max requests per time window
+ */
+class RateLimiter {
+  constructor(maxRequests, windowMs) {
+    this.maxRequests = maxRequests
+    this.windowMs = windowMs
+    this.requests = []
+  }
+
+  async waitIfNeeded() {
+    const now = Date.now()
+    // Remove requests outside the current window
+    this.requests = this.requests.filter(t => now - t < this.windowMs)
+
+    if (this.requests.length >= this.maxRequests) {
+      // Wait until the oldest request falls outside the window
+      const oldestRequest = this.requests[0]
+      const waitTime = this.windowMs - (now - oldestRequest) + 10 // +10ms buffer
+      await new Promise(resolve => setTimeout(resolve, waitTime))
+      // Clean up again after waiting
+      this.requests = this.requests.filter(t => Date.now() - t < this.windowMs)
+    }
+
+    this.requests.push(Date.now())
+  }
+}
+
+/**
+ * Create a Customer.io Analytics client
+ */
+function createCioClient(batchSize) {
+  const apiKey = process.env.CUSTOMER_IO_API_KEY
+
+  if (!apiKey) {
+    throw new Error(
+      'CUSTOMER_IO_API_KEY environment variable is required. ' +
+        'Set it to your Customer.io CDP API key.'
+    )
+  }
+
+  return new Analytics({
+    writeKey: apiKey,
+    host: 'https://cdp.customer.io',
+    maxEventsInBatch: batchSize,
+  })
+}
+
+/**
+ * Convert a CSV row to a Customer.io identify payload
+ */
+function parseOptionalBoolean(value) {
+  if (value == null || value === '') {
+    return undefined
+  }
+
+  const normalized = String(value).trim().toLowerCase()
+  if (normalized === 'true') {
+    return true
+  }
+  if (normalized === 'false') {
+    return false
+  }
+
+  return undefined
+}
+
+function parseOptionalInt(value) {
+  if (value == null || value === '') {
+    return undefined
+  }
+
+  const parsed = parseInt(value, 10)
+  return Number.isNaN(parsed) ? undefined : parsed
+}
+
+function getFirstDefinedValue(row, columnNames) {
+  for (const columnName of columnNames) {
+    if (Object.prototype.hasOwnProperty.call(row, columnName)) {
+      return row[columnName]
+    }
+  }
+
+  return undefined
+}
+
+function rowToIdentifyPayload(row) {
+  const email = getFirstDefinedValue(row, ['email'])
+  if (!email) {
+    return null
+  }
+
+  const traits = {}
+  const overleafUserId = getFirstDefinedValue(row, [
+    'user_id',
+    'userId',
+    'overleafId',
+  ])
+
+  if (email) {
+    traits.email = email
+  }
+
+  if (overleafUserId) {
+    traits.overleaf_id = overleafUserId
+  }
+
+  // Add created_at if present (keep as unix timestamp)
+  const createdAtValue = getFirstDefinedValue(row, ['created_at'])
+  if (createdAtValue) {
+    const createdAt = parseOptionalInt(createdAtValue)
+    if (createdAt !== undefined) {
+      traits.created_at = createdAt
+    }
+  }
+
+  // Add subscription status fields when present (from export_active_subscription_users_csv.mjs)
+  const stringTraitMappings = [
+    {
+      columnNames: ['plan_type', 'planType'],
+      traitName: 'plan_type',
+    },
+    {
+      columnNames: ['display_plan_type', 'displayPlanType'],
+      traitName: 'display_plan_type',
+    },
+    {
+      columnNames: ['pre_migration_plan_type', 'preMigrationPlanType'],
+      traitName: 'pre_migration_plan_type',
+    },
+    {
+      columnNames: [
+        'pre_migration_display_plan_type',
+        'preMigrationDisplayPlanType',
+      ],
+      traitName: 'pre_migration_display_plan_type',
+    },
+    {
+      columnNames: ['plan_term', 'planTerm', 'plan_term_label'],
+      traitName: 'plan_term',
+    },
+    {
+      columnNames: ['ai_plan', 'aiPlan'],
+      traitName: 'ai_plan',
+    },
+    {
+      columnNames: ['ai_plan_term', 'aiPlanTerm', 'ai_plan_term_label'],
+      traitName: 'ai_plan_term',
+    },
+    {
+      columnNames: ['group_role', 'groupRole'],
+      traitName: 'group_role',
+    },
+  ]
+
+  for (const { columnNames, traitName } of stringTraitMappings) {
+    const value = getFirstDefinedValue(row, columnNames)
+    if (value) {
+      traits[traitName] = value
+    }
+  }
+
+  const nextRenewalDateValue = getFirstDefinedValue(row, [
+    'next_renewal_date',
+    'nextRenewalDate',
+  ])
+  if (nextRenewalDateValue !== undefined) {
+    if (nextRenewalDateValue === '') {
+      traits.next_renewal_date = ''
+    } else {
+      const nextRenewalDate = parseOptionalInt(nextRenewalDateValue)
+      if (nextRenewalDate !== undefined) {
+        traits.next_renewal_date = nextRenewalDate
+      }
+    }
+  }
+
+  const expiryDateValue = getFirstDefinedValue(row, [
+    'expiry_date',
+    'expiryDate',
+  ])
+  if (expiryDateValue !== undefined) {
+    if (expiryDateValue === '') {
+      traits.expiry_date = ''
+    } else {
+      const expiryDate = parseOptionalInt(expiryDateValue)
+      if (expiryDate !== undefined) {
+        traits.expiry_date = expiryDate
+      }
+    }
+  }
+
+  const groupAiEnabledValue = getFirstDefinedValue(row, [
+    'group_ai_enabled',
+    'groupAIEnabled',
+  ])
+  if (groupAiEnabledValue !== undefined) {
+    const groupAiEnabled = parseOptionalBoolean(groupAiEnabledValue)
+    if (groupAiEnabled !== undefined) {
+      traits.group_ai_enabled = groupAiEnabled
+    }
+  }
+
+  // Add subscription preferences
+  for (const key of Object.keys(row)) {
+    if (key.startsWith('cio_subscription_preferences.topics.')) {
+      if (row[key] === 'true') {
+        traits[key] = true
+      }
+    }
+  }
+
+  // Add labsExperiments if present
+  if (row.labsExperiments) {
+    try {
+      traits.labsExperiments = JSON.parse(row.labsExperiments)
+    } catch {
+      // If it's not valid JSON, store as-is
+      traits.labsExperiments = row.labsExperiments
+    }
+  }
+
+  return {
+    // Prefer stable Overleaf user id when available, otherwise fall back to email
+    userId: overleafUserId || email,
+    email,
+    traits,
+  }
+}
+
+/**
+ * Create a CSV parser stream
+ */
+function createCsvParser(inputPath) {
+  return createReadStream(inputPath).pipe(
+    csv.parse({
+      columns: true,
+      skip_empty_lines: true,
+      relax_column_count: true,
+    })
+  )
+}
+
+/**
+ * Main script function
+ */
+function main() {
+  const argv = minimist(process.argv.slice(2), {
+    string: ['input', 'batch-size', 'skip'],
+    boolean: ['commit', 'help'],
+    alias: {
+      i: 'input',
+      h: 'help',
+    },
+  })
+
+  if (argv.help) {
+    usage()
+  }
+
+  const inputPath = argv.input
+  const commit = argv.commit
+  const dryRun = !commit
+  const batchSize = parseInt(argv['batch-size'], 10) || DEFAULT_BATCH_SIZE
+  const skipRows = parseInt(argv.skip, 10) || 0
+
+  if (!inputPath) {
+    console.error('Error: --input is required')
+    usage()
+  }
+
+  if (!fs.existsSync(inputPath)) {
+    console.error(`Error: Input file not found: ${inputPath}`)
+    process.exit(1)
+  }
+
+  if (commit && !process.env.CUSTOMER_IO_API_KEY) {
+    console.error(
+      'Error: CUSTOMER_IO_API_KEY environment variable is required when using --commit'
+    )
+    process.exit(1)
+  }
+
+  scriptRunner(
+    async trackProgress => {
+      await trackProgress('Starting batch identify to Customer.io...')
+      await trackProgress(`Input: ${inputPath}`)
+      await trackProgress(`Batch size limit: ${batchSize}`)
+      if (skipRows > 0) {
+        await trackProgress(`Skipping first ${skipRows} rows`)
+      }
+      if (dryRun) {
+        await trackProgress('DRY RUN MODE - no requests will be sent')
+      }
+
+      const rateLimiter = new RateLimiter(
+        RATE_LIMIT_REQUESTS,
+        RATE_LIMIT_WINDOW_MS
+      )
+      const client = dryRun ? null : createCioClient(batchSize)
+
+      // Listen to the 'error' event
+      if (!dryRun) {
+        client.on('error', err => {
+          console.error('cdp-analytics-node error occurred:')
+          console.error('Code:', err.code)
+          console.error('Reason:', err.reason)
+          if (err.ctx) {
+            console.error('Context:', err.ctx)
+          }
+        })
+      }
+
+      let rowNumber = 0
+      let processedCount = 0
+      let skippedCount = 0
+      let lastProgressLog = 0
+      let loggedFirstIdentifyPayload = false
+
+      const parser = createCsvParser(inputPath)
+
+      try {
+        for await (const row of parser) {
+          rowNumber++
+
+          // Skip rows if resuming
+          if (rowNumber <= skipRows) {
+            continue
+          }
+
+          const payload = rowToIdentifyPayload(row)
+          if (!payload) {
+            skippedCount++
+            continue
+          }
+
+          if (dryRun && !loggedFirstIdentifyPayload) {
+            await trackProgress(
+              `First identify payload (dry run): ${JSON.stringify(payload)}`
+            )
+            loggedFirstIdentifyPayload = true
+          }
+
+          if (!dryRun) {
+            await rateLimiter.waitIfNeeded()
+            client.identify(payload)
+          }
+
+          processedCount++
+
+          // Log progress periodically
+          if (processedCount - lastProgressLog >= PROGRESS_LOG_INTERVAL) {
+            await trackProgress(
+              `Progress: row ${rowNumber}, sent ${processedCount} requests (${skippedCount} skipped)`
+            )
+            lastProgressLog = processedCount
+          }
+        }
+      } catch (error) {
+        await trackProgress(
+          `ERROR at row ${rowNumber}: ${error.message}. Resume with --skip ${rowNumber - 1}`
+        )
+        throw error
+      }
+
+      if (!dryRun && client) {
+        await trackProgress('Flushing remaining requests...')
+        await client.closeAndFlush()
+      }
+
+      await trackProgress(
+        `Completed: processed ${processedCount} rows (${skippedCount} skipped due to missing email)`
+      )
+      if (dryRun) {
+        await trackProgress(
+          `DRY RUN complete - would have sent ${processedCount} identify requests`
+        )
+      }
+      process.exit(0)
+    },
+    { inputPath, dryRun, batchSize, skipRows }
+  ).catch(err => {
+    console.error(err)
+    process.exit(1)
+  })
+}
+
+main()
diff --git a/services/web/scripts/export_active_subscription_users_csv.mjs b/services/web/scripts/export_active_subscription_users_csv.mjs
new file mode 100644
index 0000000000..3fa23eff98
--- /dev/null
+++ b/services/web/scripts/export_active_subscription_users_csv.mjs
@@ -0,0 +1,789 @@
+import fs from 'node:fs'
+import { Parser as CSVParser } from 'json2csv'
+import minimist from 'minimist'
+import pLimit from 'p-limit'
+import Settings from '@overleaf/settings'
+import { scriptRunner } from './lib/ScriptRunner.mjs'
+import {
+  db,
+  ObjectId,
+  READ_PREFERENCE_SECONDARY,
+} from '../app/src/infrastructure/mongodb.mjs'
+import PaymentService from '../modules/subscriptions/app/src/PaymentService.mjs'
+import FeaturesHelper from '../app/src/Features/Subscription/FeaturesHelper.mjs'
+import CustomerIoPlanHelpers from '../app/src/Features/Subscription/CustomerIoPlanHelpers.mjs'
+import { isStandaloneAiAddOnPlanCode } from '../app/src/Features/Subscription/AiHelper.mjs'
+import InstitutionsGetter from '../app/src/Features/Institutions/InstitutionsGetter.mjs'
+
+const CSV_FIELDS = [
+  { label: 'user_id', value: 'userId' },
+  { label: 'email', value: 'email' },
+  { label: 'plan_type', value: 'planType' },
+  { label: 'display_plan_type', value: 'displayPlanType' },
+  {
+    label: 'pre_migration_plan_type',
+    value: 'preMigrationPlanType',
+  },
+  {
+    label: 'pre_migration_display_plan_type',
+    value: 'preMigrationDisplayPlanType',
+  },
+  { label: 'plan_term', value: 'planTerm' },
+  { label: 'ai_plan', value: 'aiPlan' },
+  { label: 'ai_plan_term', value: 'aiPlanTerm' },
+  { label: 'next_renewal_date', value: 'nextRenewalDate' },
+  { label: 'expiry_date', value: 'expiryDate' },
+  { label: 'group_ai_enabled', value: 'groupAIEnabled' },
+  { label: 'group_role', value: 'groupRole' },
+]
+const CSV_FIELD_NAMES = CSV_FIELDS.map(field => field.value)
+
+const ACTIVE_SUBSCRIPTION_STATES = ['active', 'trialing']
+const COMMONS_PLAN = getPlan(Settings.institutionPlanCode)
+
+function usage() {
+  console.log(`
+Usage:
+  node scripts/export_active_subscription_users_csv.mjs [options]
+
+Options:
+  --outputPath <path>         Output CSV path (default: /tmp/active_subscription_users.csv)
+  --concurrency <number>      Concurrent payment-provider lookups (default: 5)
+  --batchSize <number>        Number of users processed per batch (default: 500)
+  --resumeAfterUserId <id>    Resume processing strictly after this user id
+  --checkpointInterval <n>    Log resumable checkpoint every N processed users (default: 10000)
+  --append                    Append to existing output file (for resume runs)
+  --help                      Show this message
+`)
+}
+
+function parseArgs() {
+  const args = minimist(process.argv.slice(2), {
+    string: ['outputPath', 'resumeAfterUserId'],
+    boolean: ['help', 'append'],
+    default: {
+      outputPath: '/tmp/active_subscription_users.csv',
+      concurrency: 5,
+      batchSize: 500,
+      checkpointInterval: 10000,
+      append: false,
+      help: false,
+    },
+  })
+
+  if (args.help) {
+    usage()
+    process.exit(0)
+  }
+
+  return args
+}
+
+function getPlan(planCode) {
+  return Settings.plans.find(plan => plan.planCode === planCode) || null
+}
+
+function getPlanType(subscription) {
+  if (isStandaloneAiAddOnPlanCode(subscription.planCode)) {
+    return 'standalone-ai-add-on'
+  }
+  return subscription.groupPlan ? 'group' : 'individual'
+}
+
+function getPlanCadence(subscription, plan) {
+  if (plan != null) {
+    return plan.annual ? 'annual' : 'monthly'
+  }
+
+  if (isStandaloneAiAddOnPlanCode(subscription.planCode)) {
+    return subscription.planCode.includes('annual') ? 'annual' : 'monthly'
+  }
+
+  return ''
+}
+
+function userHasPremiumAiFeatures(user) {
+  return (
+    user?.features?.aiErrorAssistant === true ||
+    user?.features?.aiUsageQuota === Settings.aiFeatures.unlimitedQuota
+  )
+}
+
+async function userHasCurrentInstitutionLicence(userId, commonsCache) {
+  if (commonsCache.has(userId)) {
+    return commonsCache.get(userId)
+  }
+
+  try {
+    const institutions =
+      await InstitutionsGetter.promises.getCurrentInstitutionsWithLicence(
+        userId
+      )
+    const hasCommons = Boolean(institutions?.length)
+    commonsCache.set(userId, hasCommons)
+    return hasCommons
+  } catch (error) {
+    console.warn(
+      `Failed to evaluate commons licence for user ${userId}: ${error.message}`
+    )
+    commonsCache.set(userId, false)
+    return false
+  }
+}
+
+function isMemberOfGroupSubscription(candidates) {
+  return candidates.some(candidate => candidate.subscription?.groupPlan)
+}
+
+function getAiPlanForUser({
+  bestSubscription,
+  planType,
+  individualSubscription,
+  paymentRecord,
+  user,
+  userIsMemberOfGroupSubscription,
+  userHasActiveOverleafSubscription,
+}) {
+  const baseAiPlan = CustomerIoPlanHelpers.getAiPlanType(
+    bestSubscription,
+    individualSubscription,
+    paymentRecord,
+    user?.writefull,
+    userIsMemberOfGroupSubscription
+  )
+
+  if (baseAiPlan !== 'none') {
+    return baseAiPlan
+  }
+
+  if (!userHasActiveOverleafSubscription && userHasPremiumAiFeatures(user)) {
+    return 'ai-assist'
+  }
+
+  return 'none'
+}
+
+function getPaymentState(subscription) {
+  if (subscription?.recurlyStatus?.state) {
+    return subscription.recurlyStatus.state
+  }
+
+  if (subscription?.paymentProvider?.state) {
+    return subscription.paymentProvider.state
+  }
+
+  return null
+}
+
+function isActivePaidSubscription(subscription) {
+  const hasRecurlySubscription = Boolean(subscription?.recurlySubscription_id)
+  const hasStripeSubscription = Boolean(
+    subscription?.paymentProvider?.subscriptionId
+  )
+
+  if (!hasRecurlySubscription && !hasStripeSubscription) {
+    return false
+  }
+
+  return ACTIVE_SUBSCRIPTION_STATES.includes(getPaymentState(subscription))
+}
+
+function getGroupAiEnabled(candidates) {
+  const groupCandidates = candidates.filter(
+    candidate => getPlanType(candidate.subscription) === 'group'
+  )
+
+  if (groupCandidates.length === 0) {
+    return ''
+  }
+
+  return groupCandidates.some(candidate =>
+    CustomerIoPlanHelpers.hasPlanAiEnabled(candidate.plan)
+  )
+}
+
+function getGroupRole(candidates, userId) {
+  const groupCandidates = candidates.filter(
+    candidate => candidate.subscription?.groupPlan
+  )
+
+  if (groupCandidates.length === 0) {
+    return ''
+  }
+
+  const isGroupAdminOrManager = groupCandidates.some(candidate => {
+    const subscription = candidate.subscription
+    const adminId = subscription?.admin_id?.toString()
+    const managerIds = (subscription?.manager_ids || []).map(id =>
+      id?.toString()
+    )
+
+    return adminId === userId || managerIds.includes(userId)
+  })
+
+  return isGroupAdminOrManager ? 'admin' : 'member'
+}
+
+function chooseBestCandidate(candidates) {
+  let best = null
+
+  for (const candidate of candidates) {
+    if (best == null) {
+      best = candidate
+      continue
+    }
+
+    const candidateType = getPlanType(candidate.subscription)
+    const bestType = getPlanType(best.subscription)
+
+    if (candidateType === 'standalone-ai-add-on' && bestType !== 'free') {
+      continue
+    }
+
+    if (
+      candidateType !== 'standalone-ai-add-on' &&
+      bestType === 'standalone-ai-add-on'
+    ) {
+      best = candidate
+      continue
+    }
+
+    if (
+      FeaturesHelper.isFeatureSetBetter(
+        candidate.plan?.features || {},
+        best.plan?.features || {}
+      )
+    ) {
+      best = candidate
+    }
+  }
+
+  return best
+}
+
+function getSubscriptionQuery() {
+  return {
+    $or: [
+      {
+        recurlySubscription_id: { $exists: true, $nin: ['', null] },
+        'recurlyStatus.state': { $in: ACTIVE_SUBSCRIPTION_STATES },
+      },
+      {
+        'paymentProvider.subscriptionId': { $exists: true, $nin: ['', null] },
+        'paymentProvider.state': { $in: ACTIVE_SUBSCRIPTION_STATES },
+      },
+    ],
+  }
+}
+
+function getSubscriptionProjection() {
+  return {
+    _id: 1,
+    admin_id: 1,
+    manager_ids: 1,
+    member_ids: 1,
+    planCode: 1,
+    groupPlan: 1,
+    recurlySubscription_id: 1,
+    recurlyStatus: 1,
+    paymentProvider: 1,
+    addOns: 1,
+  }
+}
+
+function getSupplementaryUserQuery() {
+  return {
+    $or: [
+      { 'writefull.isPremium': true },
+      { 'features.aiErrorAssistant': true },
+      { 'features.aiUsageQuota': Settings.aiFeatures.unlimitedQuota },
+      {
+        emails: {
+          $elemMatch: {
+            confirmedAt: { $exists: true },
+            'affiliation.institution.confirmed': true,
+            'affiliation.licence': { $exists: true, $ne: 'free' },
+            'affiliation.pastReconfirmDate': { $ne: true },
+          },
+        },
+      },
+    ],
+  }
+}
+
+function getTargetUserIdsPipeline(resumeAfterUserId) {
+  const pipeline = [
+    { $match: getSubscriptionQuery() },
+    {
+      $project: {
+        participantIds: {
+          $setUnion: [
+            [{ $ifNull: ['$admin_id', null] }],
+            { $ifNull: ['$manager_ids', []] },
+            { $ifNull: ['$member_ids', []] },
+          ],
+        },
+      },
+    },
+    { $unwind: '$participantIds' },
+    { $match: { participantIds: { $ne: null } } },
+    { $group: { _id: '$participantIds' } },
+    {
+      $unionWith: {
+        coll: 'users',
+        pipeline: [
+          { $match: getSupplementaryUserQuery() },
+          { $project: { _id: 1 } },
+        ],
+      },
+    },
+    { $group: { _id: '$_id' } },
+  ]
+
+  if (resumeAfterUserId) {
+    let resumeId = resumeAfterUserId
+    try {
+      resumeId = new ObjectId(resumeAfterUserId)
+    } catch {
+      // leave as-is for non-ObjectId identifiers
+    }
+    pipeline.push({ $match: { _id: { $gt: resumeId } } })
+  }
+
+  pipeline.push({ $sort: { _id: 1 } })
+
+  return pipeline
+}
+
+function getTargetUserIdsCursor(resumeAfterUserId) {
+  return db.subscriptions.aggregate(
+    getTargetUserIdsPipeline(resumeAfterUserId),
+    {
+      allowDiskUse: true,
+      readPreference: READ_PREFERENCE_SECONDARY,
+    }
+  )
+}
+
+function isInvalidOrMissingSubscriptionError(error) {
+  const message = String(error?.message || '').toLowerCase()
+
+  return (
+    message.includes('no such subscription') ||
+    message.includes('invalid subscription') ||
+    message.includes('subscription not found')
+  )
+}
+
+async function getSubscriptionPaymentInfo(
+  userId,
+  subscription,
+  paymentInfoCache
+) {
+  const subscriptionId = subscription._id.toString()
+  if (paymentInfoCache.has(subscriptionId)) {
+    return {
+      ...paymentInfoCache.get(subscriptionId),
+      skip: false,
+    }
+  }
+
+  try {
+    const paymentRecord =
+      await PaymentService.promises.getPaymentFromRecord(subscription)
+    const nextRenewalDate =
+      CustomerIoPlanHelpers.getNextRenewalDateFromPaymentRecord(
+        paymentRecord
+      ) || ''
+    const paymentInfo = { nextRenewalDate, paymentRecord }
+    paymentInfoCache.set(subscriptionId, paymentInfo)
+    return { ...paymentInfo, skip: false }
+  } catch (error) {
+    if (isInvalidOrMissingSubscriptionError(error)) {
+      console.warn(
+        `Skipping user ${userId}: invalid/missing payment-provider subscription for subscription ${subscriptionId} (${error.message})`
+      )
+      return { nextRenewalDate: '', paymentRecord: null, skip: true }
+    }
+
+    console.error(
+      `Failed to get renewal date for subscription ${subscriptionId}:`,
+      error.message
+    )
+    const paymentInfo = { nextRenewalDate: '', paymentRecord: null }
+    paymentInfoCache.set(subscriptionId, paymentInfo)
+    return { ...paymentInfo, skip: false }
+  }
+}
+
+async function getUsersByIds(userIds) {
+  const objectIds = []
+  for (const userId of userIds) {
+    try {
+      objectIds.push(new ObjectId(userId))
+    } catch {
+      // ignore invalid ObjectId strings
+    }
+  }
+
+  const idFilters = []
+  if (objectIds.length > 0) {
+    idFilters.push({ _id: { $in: objectIds } })
+  }
+  if (userIds.length > 0) {
+    idFilters.push({ _id: { $in: userIds } })
+  }
+
+  if (idFilters.length === 0) {
+    return new Map()
+  }
+
+  const users = await db.users
+    .find(idFilters.length === 1 ? idFilters[0] : { $or: idFilters }, {
+      projection: {
+        _id: 1,
+        email: 1,
+        features: 1,
+        writefull: 1,
+      },
+      readPreference: READ_PREFERENCE_SECONDARY,
+    })
+    .toArray()
+
+  return new Map(users.map(user => [user._id.toString(), user]))
+}
+
+async function getActiveSubscriptionsForUserIds(userIds) {
+  const objectIds = []
+  for (const userId of userIds) {
+    try {
+      objectIds.push(new ObjectId(userId))
+    } catch {
+      // ignore invalid ObjectId strings
+    }
+  }
+
+  const idValues = objectIds.length > 0 ? objectIds : userIds
+
+  return await db.subscriptions
+    .find(
+      {
+        ...getSubscriptionQuery(),
+        $or: [
+          { admin_id: { $in: idValues } },
+          { manager_ids: { $in: idValues } },
+          { member_ids: { $in: idValues } },
+        ],
+      },
+      {
+        projection: getSubscriptionProjection(),
+        readPreference: READ_PREFERENCE_SECONDARY,
+      }
+    )
+    .toArray()
+}
+
+function buildUserCandidatesMap(subscriptions, allowedUserIds) {
+  const userCandidates = new Map()
+  const allowedUserIdsSet = new Set(allowedUserIds)
+
+  function addCandidate(userId, candidate) {
+    if (!userId || !allowedUserIdsSet.has(userId)) {
+      return
+    }
+    if (!userCandidates.has(userId)) {
+      userCandidates.set(userId, [])
+    }
+    userCandidates.get(userId).push(candidate)
+  }
+
+  for (const subscription of subscriptions) {
+    const plan = getPlan(subscription.planCode)
+    const baseCandidate = { subscription, plan }
+
+    const adminId = subscription.admin_id?.toString()
+    addCandidate(adminId, baseCandidate)
+
+    if (Array.isArray(subscription.manager_ids)) {
+      for (const managerIdRaw of subscription.manager_ids) {
+        addCandidate(managerIdRaw?.toString(), baseCandidate)
+      }
+    }
+
+    if (subscription.groupPlan && Array.isArray(subscription.member_ids)) {
+      for (const memberIdRaw of subscription.member_ids) {
+        addCandidate(memberIdRaw?.toString(), baseCandidate)
+      }
+    }
+  }
+
+  return userCandidates
+}
+
+function writeCsvRows(writeStream, rows, includeHeader) {
+  if (rows.length === 0) {
+    return
+  }
+
+  const csvParser = new CSVParser({
+    fields: includeHeader ? CSV_FIELDS : CSV_FIELD_NAMES,
+    header: includeHeader,
+    eol: '\n',
+  })
+
+  writeStream.write(`${csvParser.parse(rows)}\n`)
+}
+
+function writeCsvHeader(writeStream) {
+  writeStream.write(`${CSV_FIELDS.map(field => field.label).join(',')}\n`)
+}
+
+async function processUserBatch({
+  userIds,
+  writeStream,
+  paymentInfoCache,
+  commonsCache,
+  limit,
+  trackProgress,
+  totalUsersCount,
+  globalState,
+  checkpointInterval,
+}) {
+  const usersById = await getUsersByIds(userIds)
+  const subscriptions = await getActiveSubscriptionsForUserIds(userIds)
+  const activeSubscriptions = subscriptions.filter(isActivePaidSubscription)
+  const userCandidates = buildUserCandidatesMap(activeSubscriptions, userIds)
+
+  const rows = await Promise.all(
+    userIds.map(userId =>
+      limit(async () => {
+        const user = usersById.get(userId)
+        if (!user?.email) {
+          return null
+        }
+
+        const candidates = userCandidates.get(userId) || []
+        const bestCandidate = chooseBestCandidate(candidates)
+
+        const hasCommons = await userHasCurrentInstitutionLicence(
+          userId,
+          commonsCache
+        )
+        const commonsBeatsBestSubscription =
+          CustomerIoPlanHelpers.shouldUseCommonsBestSubscription(
+            hasCommons,
+            bestCandidate,
+            COMMONS_PLAN
+          )
+
+        const resolvedSubscription = commonsBeatsBestSubscription
+          ? null
+          : bestCandidate?.subscription
+        const resolvedPlan = commonsBeatsBestSubscription
+          ? COMMONS_PLAN
+          : bestCandidate?.plan
+
+        const bestSubscriptionForPlanType = commonsBeatsBestSubscription
+          ? { type: 'commons', plan: COMMONS_PLAN }
+          : resolvedSubscription
+            ? {
+                type: getPlanType(resolvedSubscription),
+                plan: resolvedPlan,
+              }
+            : { type: 'free' }
+        const planType = CustomerIoPlanHelpers.normalizePlanType(
+          bestSubscriptionForPlanType
+        )
+        const displayPlanType =
+          CustomerIoPlanHelpers.getFriendlyPlanName(planType) || ''
+        const planTerm = resolvedSubscription
+          ? getPlanCadence(resolvedSubscription, resolvedPlan)
+          : ''
+
+        const userIsMemberOfGroupSubscription =
+          isMemberOfGroupSubscription(candidates)
+        const userHasActiveOverleafSubscription = bestCandidate != null
+        let nextRenewalDate = ''
+        let expiryDate = ''
+        let paymentRecord = null
+        if (resolvedSubscription) {
+          const paymentInfo = await getSubscriptionPaymentInfo(
+            userId,
+            resolvedSubscription,
+            paymentInfoCache
+          )
+          if (paymentInfo.skip) {
+            return null
+          }
+          nextRenewalDate = paymentInfo.nextRenewalDate
+          paymentRecord = paymentInfo.paymentRecord
+          expiryDate =
+            CustomerIoPlanHelpers.getExpiryDateFromPaymentRecord(
+              paymentRecord
+            ) || ''
+        }
+
+        const aiPlan = getAiPlanForUser({
+          bestSubscription: bestSubscriptionForPlanType,
+          planType,
+          individualSubscription: resolvedSubscription,
+          paymentRecord,
+          user,
+          userIsMemberOfGroupSubscription,
+          userHasActiveOverleafSubscription,
+        })
+        const aiPlanTerm = CustomerIoPlanHelpers.getAiPlanCadence(
+          aiPlan,
+          bestSubscriptionForPlanType,
+          resolvedSubscription,
+          paymentRecord
+        )
+        const groupAIEnabled = getGroupAiEnabled(candidates)
+        const groupRole = getGroupRole(candidates, userId)
+
+        return {
+          userId,
+          email: user.email,
+          planType,
+          displayPlanType,
+          preMigrationPlanType: planType,
+          preMigrationDisplayPlanType: displayPlanType,
+          planTerm,
+          aiPlan,
+          aiPlanTerm: aiPlanTerm || '',
+          nextRenewalDate,
+          expiryDate,
+          groupAIEnabled,
+          groupRole,
+        }
+      })
+    )
+  )
+
+  const csvRows = []
+
+  for (const row of rows) {
+    globalState.processedCount += 1
+    if (row) {
+      csvRows.push(row)
+      globalState.writtenCount += 1
+    } else {
+      globalState.skippedCount += 1
+    }
+  }
+
+  writeCsvRows(writeStream, csvRows, globalState.shouldWriteHeader)
+  if (csvRows.length > 0) {
+    globalState.shouldWriteHeader = false
+  }
+
+  globalState.lastProcessedUserId = userIds[userIds.length - 1]
+
+  if (globalState.processedCount % checkpointInterval < userIds.length) {
+    await trackProgress(
+      `Checkpoint: processed=${globalState.processedCount}/${totalUsersCount || '?'} written=${globalState.writtenCount} skipped=${globalState.skippedCount} resumeAfterUserId=${globalState.lastProcessedUserId}`
+    )
+  }
+}
+
+async function main(trackProgress) {
+  const {
+    outputPath,
+    concurrency,
+    batchSize,
+    resumeAfterUserId,
+    checkpointInterval,
+    append,
+  } = parseArgs()
+
+  await trackProgress(
+    'Building target user cursor (subscriptions + supplementary users)'
+  )
+  if (resumeAfterUserId) {
+    await trackProgress(
+      `Resume enabled: starting after user id ${resumeAfterUserId}`
+    )
+  }
+
+  const paymentInfoCache = new Map()
+  const commonsCache = new Map()
+  const limit = pLimit(Number(concurrency) || 5)
+  const resolvedBatchSize = Math.max(1, Number(batchSize) || 500)
+  const resolvedCheckpointInterval = Math.max(
+    100,
+    Number(checkpointInterval) || 10000
+  )
+
+  const outputFileExists = fs.existsSync(outputPath)
+  const outputFileHasContent =
+    outputFileExists && fs.statSync(outputPath).size > 0
+  const writeStream = fs.createWriteStream(outputPath, {
+    flags: append ? 'a' : 'w',
+  })
+
+  const globalState = {
+    processedCount: 0,
+    writtenCount: 0,
+    skippedCount: 0,
+    lastProcessedUserId: resumeAfterUserId || null,
+    shouldWriteHeader: !append || !outputFileHasContent,
+  }
+
+  let pendingUserIds = []
+  const targetUserIdsCursor = getTargetUserIdsCursor(resumeAfterUserId)
+
+  for await (const doc of targetUserIdsCursor) {
+    pendingUserIds.push(doc._id.toString())
+
+    if (pendingUserIds.length >= resolvedBatchSize) {
+      await processUserBatch({
+        userIds: pendingUserIds,
+        writeStream,
+        paymentInfoCache,
+        commonsCache,
+        limit,
+        trackProgress,
+        totalUsersCount: null,
+        globalState,
+        checkpointInterval: resolvedCheckpointInterval,
+      })
+      pendingUserIds = []
+    }
+  }
+
+  if (pendingUserIds.length > 0) {
+    await processUserBatch({
+      userIds: pendingUserIds,
+      writeStream,
+      paymentInfoCache,
+      commonsCache,
+      limit,
+      trackProgress,
+      totalUsersCount: null,
+      globalState,
+      checkpointInterval: resolvedCheckpointInterval,
+    })
+  }
+
+  if (globalState.shouldWriteHeader) {
+    writeCsvHeader(writeStream)
+    globalState.shouldWriteHeader = false
+  }
+
+  writeStream.end()
+
+  await trackProgress(
+    `Final checkpoint: processed=${globalState.processedCount} written=${globalState.writtenCount} skipped=${globalState.skippedCount} resumeAfterUserId=${globalState.lastProcessedUserId}`
+  )
+  await trackProgress(`CSV generated: ${outputPath}`)
+  console.log(`✅ Export complete: ${outputPath}`)
+  console.log(`Rows written: ${globalState.writtenCount}`)
+}
+
+try {
+  await scriptRunner(main)
+  process.exit(0)
+} catch (error) {
+  console.error(error)
+  process.exit(1)
+}
diff --git a/services/web/test/unit/src/Project/ProjectListController.test.mjs b/services/web/test/unit/src/Project/ProjectListController.test.mjs
index c966e0a237..989f1afd53 100644
--- a/services/web/test/unit/src/Project/ProjectListController.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectListController.test.mjs
@@ -467,6 +467,34 @@ describe('ProjectListController', function () {
       await ctx.ProjectListController.projectListPage(ctx.req, ctx.res)
     })
 
+    it('should send groupRole to customer.io for group admins', async function (ctx) {
+      ctx.Features.hasFeature.withArgs('saas').returns(true)
+      ctx.SubscriptionViewModelBuilder.promises.getUsersSubscriptionDetails.resolves(
+        {
+          bestSubscription: { type: 'free' },
+          individualSubscription: null,
+          memberGroupSubscriptions: [],
+          managedGroupSubscriptions: [
+            {
+              planCode: 'group_professional',
+              membersLimit: 12,
+            },
+          ],
+        }
+      )
+      ctx.res.render = () => {}
+
+      await ctx.ProjectListController.projectListPage(ctx.req, ctx.res)
+
+      expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
+        'setUserProperties',
+        ctx.user._id,
+        sinon.match({
+          group_role: 'admin',
+        })
+      )
+    })
+
     it('should show INR Banner for Indian users with free account', async function (ctx) {
       // usersBestSubscription is only available when saas feature is present
       ctx.Features.hasFeature.withArgs('saas').returns(true)
diff --git a/services/web/test/unit/src/Subscription/FeaturesUpdater.test.mjs b/services/web/test/unit/src/Subscription/FeaturesUpdater.test.mjs
index e8cef6f13b..f60d2ad451 100644
--- a/services/web/test/unit/src/Subscription/FeaturesUpdater.test.mjs
+++ b/services/web/test/unit/src/Subscription/FeaturesUpdater.test.mjs
@@ -9,6 +9,7 @@ const MODULE_PATH = '../../../../app/src/Features/Subscription/FeaturesUpdater'
 
 describe('FeaturesUpdater', function () {
   beforeEach(async function (ctx) {
+    ctx.renewalDate = new Date('2099-04-01T00:00:00Z')
     ctx.v1UserId = 12345
     ctx.user = {
       _id: new ObjectId(),
@@ -17,7 +18,12 @@ describe('FeaturesUpdater', function () {
     }
     ctx.aiAddOn = { addOnCode: AI_ADD_ON_CODE, quantity: 1 }
     ctx.subscriptions = {
-      individual: { planCode: 'individual-plan' },
+      individual: {
+        planCode: 'individual-plan',
+        groupPlan: false,
+        recurlySubscription_id: 'sub-individual',
+        recurlyStatus: { state: 'active' },
+      },
       group1: { planCode: 'group-plan-1', groupPlan: true },
       group2: { planCode: 'group-plan-2', groupPlan: true },
       noDropbox: { planCode: 'no-dropbox' },
@@ -115,6 +121,7 @@ describe('FeaturesUpdater', function () {
     ctx.UserGetter = {
       promises: {
         getUser: sinon.stub().resolves(null),
+        getWritefullData: sinon.stub().resolves(null),
       },
     }
     ctx.UserGetter.promises.getUser.withArgs(ctx.user._id).resolves(ctx.user)
@@ -126,12 +133,25 @@ describe('FeaturesUpdater', function () {
       setUserPropertyForUserInBackground: sinon.stub(),
     }
     ctx.Modules = {
-      promises: { hooks: { fire: sinon.stub().resolves() } },
+      promises: { hooks: { fire: sinon.stub().resolves([]) } },
     }
+    ctx.Modules.promises.hooks.fire
+      .withArgs('getPaymentFromRecordPromise', ctx.subscriptions.individual)
+      .resolves([
+        {
+          subscription: {
+            state: 'active',
+            periodEnd: ctx.renewalDate,
+          },
+        },
+      ])
     ctx.SubscriptionViewModelBuilder = {
       promises: {
         getUsersSubscriptionDetails: sinon.stub().resolves({
           bestSubscription: { type: 'individual' },
+          individualSubscription: ctx.subscriptions.individual,
+          memberGroupSubscriptions: [],
+          managedGroupSubscriptions: [],
         }),
       },
     }
@@ -419,36 +439,115 @@ describe('FeaturesUpdater', function () {
         ).to.have.been.calledWith(ctx.user._id, 'feature-set', 'all')
       })
 
-      it('should sync features to customer.io', function (ctx) {
+      it('should sync subscription properties to customer.io', function (ctx) {
         expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
           'setUserProperties',
           ctx.user._id,
-          {
-            features: ctx.Settings.features.all,
-            'best-subscription-type': 'individual',
-            overleafId: ctx.user._id,
-          }
+          sinon.match({
+            plan_type: 'individual',
+            display_plan_type: 'individual',
+            ai_plan: 'none',
+            next_renewal_date: Math.floor(ctx.renewalDate.getTime() / 1000),
+            expiry_date: '',
+            features: sinon.match.object,
+          })
         )
       })
     })
 
-    describe('when user has an email', function () {
+    describe('when the individual subscription has a pending cancellation', function () {
       beforeEach(async function (ctx) {
-        ctx.user.email = 'user@example.com'
+        const pendingCancellationSubscription = {
+          ...ctx.subscriptions.individual,
+          recurlyStatus: { state: 'canceled' },
+        }
+        ctx.SubscriptionViewModelBuilder.promises.getUsersSubscriptionDetails.resolves(
+          {
+            bestSubscription: { type: 'individual' },
+            individualSubscription: pendingCancellationSubscription,
+            memberGroupSubscriptions: [],
+            managedGroupSubscriptions: [],
+          }
+        )
+        ctx.Modules.promises.hooks.fire
+          .withArgs(
+            'getPaymentFromRecordPromise',
+            pendingCancellationSubscription
+          )
+          .resolves([
+            {
+              subscription: {
+                state: 'canceled',
+                periodEnd: ctx.renewalDate,
+              },
+            },
+          ])
+
         await ctx.FeaturesUpdater.promises.refreshFeatures(ctx.user._id, 'test')
       })
 
-      it('should include email in customer.io properties', function (ctx) {
+      it('should sync expiry_date and blank next_renewal_date in customer.io', function (ctx) {
         expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
           'setUserProperties',
           ctx.user._id,
+          sinon.match({
+            plan_type: 'individual',
+            display_plan_type: 'individual',
+            ai_plan: 'none',
+            next_renewal_date: '',
+            expiry_date: Math.floor(ctx.renewalDate.getTime() / 1000),
+            features: sinon.match.object,
+          })
+        )
+      })
+    })
+
+    describe('when the user is in a group subscription', function () {
+      beforeEach(async function (ctx) {
+        ctx.SubscriptionViewModelBuilder.promises.getUsersSubscriptionDetails.resolves(
           {
-            features: ctx.Settings.features.all,
-            'best-subscription-type': 'individual',
-            overleafId: ctx.user._id,
-            email: 'user@example.com',
+            bestSubscription: {
+              type: 'group',
+              plan: {
+                planCode: 'group-plan-1',
+                groupPlan: true,
+                membersLimit: 5,
+              },
+              subscription: {
+                teamName: 'Team Alpha',
+              },
+            },
+            memberGroupSubscriptions: [
+              {
+                planCode: 'group-plan-1',
+                teamName: 'Team Alpha',
+                membersLimit: 8,
+              },
+            ],
+            managedGroupSubscriptions: [],
+            individualSubscription: null,
           }
         )
+        await ctx.FeaturesUpdater.promises.refreshFeatures(ctx.user._id, 'test')
+      })
+
+      it('should sync groupSize to customer.io', function (ctx) {
+        expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
+          'setUserProperties',
+          ctx.user._id,
+          sinon.match({
+            plan_type: 'group-standard',
+            display_plan_type: 'Group Standard',
+            plan_term_label: 'monthly',
+            ai_plan: 'none',
+            group_ai_enabled: false,
+            group_size: 8,
+            next_renewal_date: '',
+            expiry_date: '',
+            features: sinon.match.object,
+            overleaf_id: ctx.user._id,
+          })
+        )
       })
     })
 
diff --git a/services/web/test/unit/src/Templates/TemplatesController.test.mjs b/services/web/test/unit/src/Templates/TemplatesController.test.mjs
index 5d354718b5..1ced1067c4 100644
--- a/services/web/test/unit/src/Templates/TemplatesController.test.mjs
+++ b/services/web/test/unit/src/Templates/TemplatesController.test.mjs
@@ -1,6 +1,5 @@
 import { vi, expect } from 'vitest'
 import sinon from 'sinon'
-import ProjectHelper from '../../../../app/src/Features/Project/ProjectHelper.mjs'
 
 const modulePath =
   '../../../../app/src/Features/Templates/TemplatesController.mjs'
@@ -9,8 +8,12 @@ describe('TemplatesController', function () {
   beforeEach(async function (ctx) {
     ctx.user_id = 'user-id'
 
+    ctx.ProjectHelper = {
+      compilerFromV1Engine: sinon.stub(),
+    }
+
     vi.doMock('../../../../app/src/Features/Project/ProjectHelper', () => ({
-      default: ProjectHelper,
+      default: ctx.ProjectHelper,
     }))
 
     vi.doMock(