websocketd is the WebSocket daemon

It takes care of handling the WebSocket connections,
launching your programs to handle the WebSockets,
and passing messages between programs and web-browser.

WebSockets for PHP

Ratchet is a loosely coupled PHP library providing developers with tools to create real time, bi-directional applications between clients and servers over WebSockets. This is not your Grandfather's Internet.

WAMP is an open WebSocket subprotocol that provides two asynchronous messaging patterns: RPC and PubSub.