diff --git a/services/clsi/.dockerignore b/services/clsi/.dockerignore
index 386f26df30..ba1c3442de 100644
--- a/services/clsi/.dockerignore
+++ b/services/clsi/.dockerignore
@@ -5,5 +5,3 @@ gitrev
 .npm
 .nvmrc
 nodemon.json
-app.js
-**/js/*
diff --git a/services/clsi/.eslintrc b/services/clsi/.eslintrc
new file mode 100644
index 0000000000..42a4b5cace
--- /dev/null
+++ b/services/clsi/.eslintrc
@@ -0,0 +1,65 @@
+// this file was auto-generated, do not edit it directly.
+// instead run bin/update_build_scripts from
+// https://github.com/sharelatex/sharelatex-dev-environment
+// Version: 1.3.5
+{
+  "extends": [
+    "standard",
+    "prettier",
+    "prettier/standard"
+  ],
+  "parserOptions": {
+    "ecmaVersion": 2017
+  },
+  "plugins": [
+    "mocha",
+    "chai-expect",
+    "chai-friendly"
+  ],
+  "env": {
+    "node": true,
+    "mocha": true
+  },
+  "rules": {
+    // Swap the no-unused-expressions rule with a more chai-friendly one
+    "no-unused-expressions": 0,
+    "chai-friendly/no-unused-expressions": "error"
+  },
+  "overrides": [
+    {
+      // Test specific rules
+      "files": ["test/**/*.js"],
+      "globals": {
+        "expect": true
+      },
+      "rules": {
+        // mocha-specific rules
+        "mocha/handle-done-callback": "error",
+        "mocha/no-exclusive-tests": "error",
+        "mocha/no-global-tests": "error",
+        "mocha/no-identical-title": "error",
+        "mocha/no-nested-tests": "error",
+        "mocha/no-pending-tests": "error",
+        "mocha/no-skipped-tests": "error",
+        "mocha/no-mocha-arrows": "error",
+
+        // chai-specific rules
+        "chai-expect/missing-assertion": "error",
+        "chai-expect/terminating-properties": "error",
+
+        // prefer-arrow-callback applies to all callbacks, not just ones in mocha tests.
+        // we don't enforce this at the top-level - just in tests to manage `this` scope
+        // based on mocha's context mechanism
+        "mocha/prefer-arrow-callback": "error"
+      }
+    },
+    {
+      // Backend specific rules
+      "files": ["app/**/*.js", "app.js", "index.js"],
+      "rules": {
+        // don't allow console.log in backend code
+        "no-console": "error"
+      }
+    }
+  ]
+}
diff --git a/services/clsi/.prettierrc b/services/clsi/.prettierrc
new file mode 100644
index 0000000000..5845b82113
--- /dev/null
+++ b/services/clsi/.prettierrc
@@ -0,0 +1,8 @@
+# This file was auto-generated, do not edit it directly.
+# Instead run bin/update_build_scripts from
+# https://github.com/sharelatex/sharelatex-dev-environment
+# Version: 1.3.5
+{
+  "semi": false,
+  "singleQuote": true
+}
diff --git a/services/clsi/Dockerfile b/services/clsi/Dockerfile
index 9dcf70c3f9..9faccd4957 100644
--- a/services/clsi/Dockerfile
+++ b/services/clsi/Dockerfile
@@ -21,7 +21,6 @@ RUN npm install --quiet
 COPY . /app
 
 
-RUN npm run compile:all
 
 FROM base
 
diff --git a/services/clsi/Jenkinsfile b/services/clsi/Jenkinsfile
index 47a663829d..c7b961eb19 100644
--- a/services/clsi/Jenkinsfile
+++ b/services/clsi/Jenkinsfile
@@ -37,6 +37,13 @@ pipeline {
       }
     }
 
+    stage('Linting') {
+      steps {
+        sh 'DOCKER_COMPOSE_FLAGS="-f docker-compose.ci.yml" make format'
+        sh 'DOCKER_COMPOSE_FLAGS="-f docker-compose.ci.yml" make lint'
+      }
+    }
+
     stage('Unit Tests') {
       steps {
         sh 'DOCKER_COMPOSE_FLAGS="-f docker-compose.ci.yml" make test_unit'
diff --git a/services/clsi/Makefile b/services/clsi/Makefile
index 13785bc22e..88234f2a23 100644
--- a/services/clsi/Makefile
+++ b/services/clsi/Makefile
@@ -16,12 +16,17 @@ DOCKER_COMPOSE := BUILD_NUMBER=$(BUILD_NUMBER) \
 clean:
 	docker rmi ci/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
 	docker rmi gcr.io/overleaf-ops/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
-	rm -f app.js
-	rm -rf app/js
-	rm -rf test/unit/js
-	rm -rf test/acceptance/js
 
-test: test_unit test_acceptance
+format:
+	$(DOCKER_COMPOSE) run --rm test_unit npm run format
+
+format_fix:
+	$(DOCKER_COMPOSE) run --rm test_unit npm run format:fix
+
+lint:
+	$(DOCKER_COMPOSE) run --rm test_unit npm run lint
+
+test: format lint test_unit test_acceptance
 
 test_unit:
 	@[ ! -d test/unit ] && echo "clsi has no unit tests" || $(DOCKER_COMPOSE) run --rm test_unit
diff --git a/services/clsi/buildscript.txt b/services/clsi/buildscript.txt
index e6e202ca70..9cccf33aa7 100644
--- a/services/clsi/buildscript.txt
+++ b/services/clsi/buildscript.txt
@@ -1,6 +1,6 @@
 clsi
 --public-repo=True
---language=coffeescript
+--language=es
 --env-add=
 --node-version=10.19.0
 --acceptance-creds=None
diff --git a/services/clsi/nodemon.json b/services/clsi/nodemon.json
index 98db38d71b..5826281b84 100644
--- a/services/clsi/nodemon.json
+++ b/services/clsi/nodemon.json
@@ -10,10 +10,9 @@
   },
 
   "watch": [
-    "app/coffee/",
-    "app.coffee",
+    "app/js/",
+    "app.js",
     "config/"
   ],
-  "ext": "coffee"
-
+  "ext": "js"
 }
diff --git a/services/clsi/package.json b/services/clsi/package.json
index 24984d1f50..55395380c5 100644
--- a/services/clsi/package.json
+++ b/services/clsi/package.json
@@ -7,17 +7,15 @@
     "url": "https://github.com/sharelatex/clsi-sharelatex.git"
   },
   "scripts": {
-    "compile:app": "([ -e app/coffee ] && coffee -m $COFFEE_OPTIONS -o app/js -c app/coffee || echo 'No CoffeeScript folder to compile') && ( [ -e app.coffee ] && coffee -m $COFFEE_OPTIONS -c app.coffee || echo 'No CoffeeScript app to compile')",
-    "start": "npm run compile:app && node $NODE_APP_OPTIONS app.js",
-    "test:acceptance:_run": "mocha --recursive --reporter spec --timeout 30000 --exit $@ test/acceptance/js",
-    "test:acceptance": "npm run compile:app && npm run compile:acceptance_tests && npm run test:acceptance:_run -- --grep=$MOCHA_GREP",
-    "test:unit:_run": "mocha --recursive --reporter spec --exit $@ test/unit/js",
-    "test:unit": "npm run compile:app && npm run compile:unit_tests && npm run test:unit:_run -- --grep=$MOCHA_GREP",
-    "compile:unit_tests": "[ ! -e test/unit/coffee ] &&  echo 'No unit tests to compile' || coffee -o test/unit/js -c test/unit/coffee",
-    "compile:acceptance_tests": "[ ! -e test/acceptance/coffee ] && echo 'No acceptance tests to compile' || coffee -o test/acceptance/js -c test/acceptance/coffee",
-    "compile:all": "npm run compile:app && npm run compile:unit_tests && npm run compile:acceptance_tests && npm run compile:smoke_tests",
+    "start": "node $NODE_APP_OPTIONS app.js",
+    "test:acceptance:_run": "mocha --recursive --reporter spec --timeout 15000 --exit $@ test/acceptance/js",
+    "test:acceptance": "npm run test:acceptance:_run -- --grep=$MOCHA_GREP",
+    "test:unit:_run": "mocha --recursive --reporter spec $@ test/unit/js",
+    "test:unit": "npm run test:unit:_run -- --grep=$MOCHA_GREP",
     "nodemon": "nodemon --config nodemon.json",
-    "compile:smoke_tests": "[ ! -e test/smoke/coffee ] &&  echo 'No smoke tests to compile' || coffee -o test/smoke/js -c test/smoke/coffee"
+    "lint": "node_modules/.bin/eslint .",
+    "format": "node_modules/.bin/prettier-eslint '**/*.js' --list-different",
+    "format:fix": "node_modules/.bin/prettier-eslint '**/*.js' --write"
   },
   "author": "James Allen <james@sharelatex.com>",
   "dependencies": {