Ws is a simple to use websocket implementation, up-to-date against RFC-6455, and probably the fastest WebSocket library for Node.js.

Passes the quite extensive Autobahn test suite. See http://einaros.github.com/ws for the full reports.

It also provides wscat, a command-line tool which can either act as a server or a client, and is useful for debugging websocket services.

Node.js is an event-based server-side javascript engine.