Pusher is a hosted service that makes it super-easy to add real-time data and functionality to web and mobile applications.
Pusher sits as a real-time layer between your servers and your clients. Pusher maintains persistent connections to the clients - over WebSocket if possible and falling back to HTTP-based connectivity - so that as soon as your servers have new data that they want to push to the clients they can do, instantly via Pusher.
Pusher offers libraries to integrate into all the main runtimes and frameworks. PHP, Ruby, Python, Java, .NET, Go and Node on the server and JavaScript, Objective-C (iOS) and Java (Android) on the client.
Pusher is a highly scalable real-time solution established in 2010 and has lots of awesome customers including GitHub, MailChimp, CodeShip, The Financial Times, UserVoice, Travis CI and QuizUp.