 <p>The docs on the repo were updated three days ago, changing the reference from 'socket.io' to 'socket.io-node', so it appears things are in flux.</p> <p>To get the functionality you need, you might check out eventedsocket at <a href="https://github.com/torgeir/eventedsocket" rel="nofollow">https://github.com/torgeir/eventedsocket</a> (npm install eventedsocket)</p> <p>From the README.md:</p> <p>Eventedsocket adds event like behavior to your socket.io connection, allowing for events to be sent from client(s) to server or server to client(s). Your custom events along with the desired data are communicated as json over whatever protocol socket.io might choose.</p>