A webhook is an HTTP callback, a simple yet powerful mechanism that allows a web application or service to provide real-time information to other applications or services by pushing data to them.

Webhooks are triggered by specific events within a software environment—when event X occurs, it prompts an immediate data transmission from one application to another over the web. Essentially, they operate as a "phone call" made directly from one application to another to share data or trigger actions automatically when certain conditions are met, without the need for continuous polling or manual data retrieval.

In the context of integrating services for example in the case of integrating Cal.com and Supabase, a webhook could be used to inform your application about events such as new appointments or changes in Cal.com. This notification allows the receiving application to automatically process the information, update databases, or even trigger additional workflows without requiring manual intervention, thereby enabling a more dynamic and real-time data interaction between the connected platforms.

By facilitating instant communications and actions triggered by specific events, webhooks substantially reduce the complexity and time associated with setting up integrations, thus directly contributing to a more favorable developer experience.