ReactPHP

ReactPHP is a low-level library for event-driven programming in PHP. At its core is an event loop, on top of which it provides low-level utilities, such as: Streams abstraction, async DNS resolver, network client/server, HTTP client/server and interaction with processes. Third-party libraries can use these components to create async network clients/servers and more. ReactPHP is production ready and battle-tested with millions of installations from all kinds of projects around the world. Its event-driven architecture makes it a perfect fit for efficient network servers and clients handling hundreds or thousands of concurrent connections, long-running applications and many other forms of cooperative multitasking with non-blocking I/O operations. What makes ReactPHP special is its vivid ecosystem with hundreds of third-party libraries allowing you to integrate with many existing systems, such as common network services, database systems and other third-party APIs.