What is the point of using socket.io today? Three years ago WebSocket support wasn't universally available, so you needed XHR etc. as a fallback. But now it's 2015 and everything supports WebSocket. Why not just use them directly? They have a super simple API. (see: <a href="http://ajf.me/websocket" rel="nofollow">http://ajf.me/websocket</a> - a page I made about them)<p>If you're worried about firewall/proxy traversal, use wss:// (WebSocket over TLS), which not only traverses, but doesn't cause a speed and latency downgrade like falling back to XHR does.<p>I realise some sites might need to use socket.io if they're targeting legacy platforms, but that's an ever-shrinking slice of the market. For most sites it is probably overkill.