Web Hooks

Web hooks are user-defined callbacks over HTTP. They’re intended to, in a sense, “jailbreak” our web applications to become more extensible, customizable, and ultimately more useful. Conceptually, web applications only have a request-based “input” mechanism: web APIs. They lack an event-based output mechanism, and this is the role of web hooks. People talk about Unix pipes for the web, but they forget: pipes are based on standard input and standard output. Feeds are not a sufficient form of output for this, which is partly why Yahoo Pipes was not the game changer some people expected. Instead, we need adoption of a simple, real-time, event-driven mechanism, and web hooks seem to be the answer. Web hooks are bringing a new level of event-based programming to the web.

http://blog.webhooks.org/about/