Using Socket.IO for Real-Time Features

A plain WebSocket client cannot talk to a Socket.IO server. When a test pointed the standard WebSocket class at the Socket.IO endpoint of the server below, the first frame it received was not a chat message but this:

0{"sid":"pXuWYgFoXkLGtP50AAAA","upgrades":[],"pingInterval":25000,"pingTimeout":20000,"maxPayload":1000000}

Socket.IO is a library for real-time communication with its own protocol. It can use a WebSocket connection to carry its messages, but every message is wrapped in that protocol, so both ends must use Socket.IO