Ratchet

Ratchet is a loosely-coupled PHP library for building realtime, bi-directional applications between clients and servers over WebSockets. It sits on top of ReactPHP’s event loop and socket layer to keep persistent connections open, letting a PHP process push data to many connected clients without polling.

Rather than a single monolithic server, Ratchet is composed of stackable components — an IO server, an HTTP request parser, a WebSocket layer, and higher-level protocols like WAMP — so you assemble exactly the pipeline your app needs. Your application logic implements a simple MessageComponentInterface with onOpen, onMessage, onClose, and onError hooks.

What You Get

• An event-driven WebSocket server built on the ReactPHP event loop
• A stackable component pipeline (IoServer, HttpServer, WsServer, WampServer)
• A simple MessageComponentInterface with onOpen/onMessage/onClose/onError hooks
• WAMP (WebSocket Application Messaging Protocol) support for pub/sub and RPC
• Session integration and origin/IP checking for connection security

Common Use Cases

• Chat servers and messaging systems that push messages to many clients instantly
• Live dashboards, notifications, and activity feeds that update without page refreshes
• Multiplayer game backends and collaborative editing tools
• Pub/sub and RPC over WebSockets using the WAMP layer

Under The Hood

Architecture - Ratchet is a decorator-style pipeline. An IoServer (src/Ratchet/Server/IoServer.php) owns the ReactPHP event loop and raw socket, wrapping an HttpServer that parses incoming HTTP requests (HttpRequestParser, Router), which in turn wraps a WsServer performing the WebSocket handshake and framing, which finally delegates to your application component implementing MessageComponentInterface. Each layer is an AbstractConnectionDecorator so connection state flows cleanly down the stack, and higher-level protocols like WAMP build on the same interfaces.

Tech Stack - PHP (>=5.4.2, still compatible with modern versions), built on react/socket and react/event-loop for non-blocking IO, ratchet/rfc6455 for WebSocket protocol framing, guzzlehttp/psr7 for HTTP messages, and symfony/http-foundation plus symfony/routing for session and routing integration. Tests use PHPUnit.

Code Quality - The source is organized by concern (Http, Server, Session, Wamp, WebSocket) behind small interfaces (ComponentInterface, MessageComponentInterface, ConnectionInterface). Multiple Symfony-version-specific session storage classes show deliberate backward-compatibility work. The project is stable and mature, with the trade-off that its release cadence is slow.

API Design - The developer-facing contract is intentionally minimal: implement onOpen, onMessage, onClose, and onError, then wrap your component in the server stack (often via App or IoServer::factory). This makes a basic echo or chat server only a few lines, while the decorator model keeps advanced composition possible for teams that need HTTP routing, WAMP, or custom middleware.