A server side alternative implementation of socket.io
phpSocket.io is a PHP implementation of the popular Socket.IO real-time communication protocol. It enables real-time, bidirectional communication between web clients and servers using WebSockets, with a syntax and structure similar to the original Node.js version. Built on top of Workerman, phpSocket.io is capable of handling thousands of concurrent connections and is ideal for building chat apps, live notifications, and collaborative tools in 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. Write your own chat (aka "Hello World!" for sockets) application in a matter of minutes. After understanding "the new flow", event driven programming, compared to traditional HTTP request/response - writing any application on top of Ratchet becomes fast and easy.