websockets is a library for developing WebSocket servers and clients in Python. It implements RFC 6455 with a focus on correctness and simplicity. It passes the Autobahn Testsuite.

Built on top on Python’s asynchronous I/O support introduced in PEP 3156, it provides an API based on coroutines, making it easy to write highly concurrent applications.

I've uploaded my @RealtimeConf sidedeck at

Excellent (mind blowing!) article about using EventSource in the real world.

Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.