diff --git a/services/contacts/app.js b/services/contacts/app.js
index 7465c9fa64..e4d8fa7651 100644
--- a/services/contacts/app.js
+++ b/services/contacts/app.js
@@ -1,45 +1,60 @@
-Metrics    = require "metrics-sharelatex"
-Metrics.initialize("contacts")
+/*
+ * decaffeinate suggestions:
+ * DS102: Remove unnecessary code created because of implicit returns
+ * DS207: Consider shorter variations of null checks
+ * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
+ */
+const Metrics    = require("metrics-sharelatex");
+Metrics.initialize("contacts");
 
-Settings   = require "settings-sharelatex"
-logger     = require "logger-sharelatex"
-express    = require "express"
-bodyParser = require "body-parser"
-Errors     = require "./app/js/Errors"
-HttpController = require "./app/js/HttpController"
+const Settings   = require("settings-sharelatex");
+const logger     = require("logger-sharelatex");
+const express    = require("express");
+const bodyParser = require("body-parser");
+const Errors     = require("./app/js/Errors");
+const HttpController = require("./app/js/HttpController");
 
-Path       = require "path"
+const Path       = require("path");
 
 
-logger.initialize("contacts")
-Metrics.event_loop?.monitor(logger)
+logger.initialize("contacts");
+if (Metrics.event_loop != null) {
+	Metrics.event_loop.monitor(logger);
+}
 
-app = express()
+const app = express();
 
-app.use Metrics.http.monitor(logger)
+app.use(Metrics.http.monitor(logger));
 
-Metrics.injectMetricsRoute(app)
+Metrics.injectMetricsRoute(app);
 
-app.get  '/user/:user_id/contacts', HttpController.getContacts
-app.post '/user/:user_id/contacts', bodyParser.json(limit: "2mb"), HttpController.addContact
+app.get('/user/:user_id/contacts', HttpController.getContacts);
+app.post('/user/:user_id/contacts', bodyParser.json({limit: "2mb"}), HttpController.addContact);
 
-app.get '/status', (req, res)->
-	res.send('contacts is alive')
+app.get('/status', (req, res) => res.send('contacts is alive'));
 
-app.use (error, req, res, next) ->
-	logger.error err: error, "request errored"
-	if error instanceof Errors.NotFoundError
-		res.send 404
-	else
-		res.send(500, "Oops, something went wrong")
+app.use(function(error, req, res, next) {
+	logger.error({err: error}, "request errored");
+	if (error instanceof Errors.NotFoundError) {
+		return res.send(404);
+	} else {
+		return res.send(500, "Oops, something went wrong");
+	}
+});
 
-port = Settings.internal.contacts.port
-host = Settings.internal.contacts.host
+const {
+    port
+} = Settings.internal.contacts;
+const {
+    host
+} = Settings.internal.contacts;
 
 
-if !module.parent # Called directly
-	app.listen port, host, (error) ->
-		throw error if error?
-		logger.info "contacts starting up, listening on #{host}:#{port}"
+if (!module.parent) { // Called directly
+	app.listen(port, host, function(error) {
+		if (error != null) { throw error; }
+		return logger.info(`contacts starting up, listening on ${host}:${port}`);
+	});
+}
 
-module.exports = app
+module.exports = app;
diff --git a/services/contacts/config/settings.defaults.js b/services/contacts/config/settings.defaults.js
index 7768f915ec..cac7ea2aef 100644
--- a/services/contacts/config/settings.defaults.js
+++ b/services/contacts/config/settings.defaults.js
@@ -1,11 +1,15 @@
-http = require('http')
-http.globalAgent.maxSockets = 300
+const http = require('http');
+http.globalAgent.maxSockets = 300;
 
-module.exports =
-	internal:
-		contacts:
-			port: 3036
-			host: process.env["LISTEN_ADDRESS"] or "localhost"
+module.exports = {
+	internal: {
+		contacts: {
+			port: 3036,
+			host: process.env["LISTEN_ADDRESS"] || "localhost"
+		}
+	},
 
-	mongo:
-		url: process.env['MONGO_CONNECTION_STRING'] or "mongodb://#{process.env["MONGO_HOST"] or "localhost"}/sharelatex"
+	mongo: {
+		url: process.env['MONGO_CONNECTION_STRING'] || `mongodb://${process.env["MONGO_HOST"] || "localhost"}/sharelatex`
+	}
+};