diff --git a/README.md b/README.md
index 9ddf7744..606cbcd9 100644
--- a/README.md
+++ b/README.md
@@ -144,7 +144,7 @@ npm i yjs y-websocket
 Start the y-websocket server:
 
 ```sh
-PORT=1234 node ./node_modules/y-websocket/bin/server.js
+PORT=1234 node ./node_modules/y-websocket/bin/server.cjs
 ```
 
 ### Example: Observe types