diff --git a/Dockerfile b/Dockerfile
index 950fdbd..fb935f7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,5 @@
 FROM node:alpine
-EXPOSE 4242
+EXPOSE 4000
 COPY . .
 RUN npm install
 CMD npm start
diff --git a/index.mjs b/index.mjs
index d2b5822..e5da0da 100644
--- a/index.mjs
+++ b/index.mjs
@@ -9,7 +9,7 @@ const authorizer = new Authorizer({
 
 const startServer = async () => {
   const server = await Server.configure({
-    port: 4242,
+    port: process.env.PORT || 4000,
     async onConnect({ connection }) {
       connection.requiresAuthentication = true;
     },