Like inetd, but for WebSockets. Turn any application that uses STDIO/STDOUT into a WebSocket server.

Ratchet is a PHP 5.3 library for asynchronously serving WebSockets. It provides tools to create real time, bi-directional applications between clients and servers. Performance has been improving, particularly in PHP 5.4, and works well for small to medium size scale applications so far. It leverages Symfony http foundation and Guzzle. Ratchet is powered by React http://reactphp.org/ an Event-driven, non-blocking I/O library (compared to traditional HTTP request/response). React has many components you can use, Laravel uses's React's Async component.