The current version of this library does not support socket.io v1.0. So if you want to use socket.io-objc, please fall back to v0.9.x. Today (15/03/09) the Socket.io guys announced their own iOS library - grab it while it's still hot: github.com/socketio/socket.io-client-swift Socket.IO / Objective C Library Interface to communicate between Objective C and Socket.IO with the help of websockets or