diff --git a/backend/.env.example b/backend/.env.example
index f69c034..7bea792 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -1,3 +1,2 @@
-DEFAULT_PORT=
 REDIS_HOST=
 REDIS_PORT=
diff --git a/backend/package.json b/backend/package.json
index 4faf9a4..a886311 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -10,6 +10,7 @@
   "author": "CKSource (http://cksource.com/)",
   "license": "MIT",
   "dependencies": {
+    "dotenv": "^8.0.0",
     "express": "^4.16.4",
     "ioredis": "^4.9.5",
     "socket.io": "^2.2.0",
@@ -17,7 +18,6 @@
   },
   "devDependencies": {
     "chai": "^4.2.0",
-    "dotenv": "^8.0.0",
     "mocha": "^6.1.4"
   }
 }
diff --git a/backend/src/index.js b/backend/src/index.js
index 020ca3f..d8d4a3f 100644
--- a/backend/src/index.js
+++ b/backend/src/index.js
@@ -65,8 +65,10 @@ io.on( 'connection', socket => {
 	} );
 } );
 
-http.listen( process.env.DEFAULT_PORT, () => {
-	console.log( 'listening on *:' + process.env.DEFAULT_PORT );
+const port = process.env.PORT || 3000;
+
+http.listen( port, () => {
+	console.log( 'listening on *:' + port );
 } );
 
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