In web development, webhooks are a method of adding or altering the behavior of web pages or web applications with custom callbacks.
Callbacks can in turn be maintained, modified, and managed by 3rd-party users and developers who are not part of the core development team of the application or page in use. Webhooks are usually written in JSON and requests are done as an HTTP POST request.
Webhooks are often triggered by events, for example, a new component being pushed to a repository or page.
When events occur, the source site makes an HTTP request to the URL configured for the webhook. Users can configure them to cause events on one site to invoke further actions. Common uses include build triggers for continuous integration systems and notify bug tracking systems.
Because webhooks use HTTP, they can be easily integrated into web services without the need to add new infrastructure, making them widely used.