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Pusher is a simple hosted API for quickly, easily and securely adding realtime bi-directional functionality via WebSockets to web and mobile apps, or any other Internet connected device. These technologies are also known as real-time push or real-time messaging technologies.
 
Pusher offers a rich suite of client libraries that can be used within many applications, including a JavaScript client library for web and HTML5 apps.
 
Pusher offers an event based abstraction layered upon WebSockets that makes it simple to bind UI interactions to events that are triggered from any client or server.
 
Pusher uses WebSockets (with a fallback to Flash in the JavaScript library) to future proof applications and make it easy to add bi-directional communication to applications whilst keeping data usage to a minimum.
 
As well as a WebSockets API, Pusher have a REST API for publishing messages. This is ideally suited to web server technologies and Pusher have a set of libraries in many common languages to help do this.
 
Pusher have a simple Publish/Subscribe model based on channels that allows filtering and controlling how people receive messages.
 
Pusher supply functionality such as authentication mechanisms for private channels, and presence functionality for keeping track of who's online.
 
Pusher also offer tools for easily debugging the complex messaging that can take place in bi-directional real-time applications.