Webhooks are used as a signal between applications. You can see it as a callback from a different context. This call is made with the HTTP protocol (possibly with SSL). An attempt is made to provide information as efficiently as possible and in real time, and JSON is usually used as a data format.
The strength lies in the fact that as few operations as possible are necessary in order to get feedback. Usually, the most work lies in the implementation of the signal.
For a proof of concept, consider the following. Let's assume that when we push new code to GitLab, we have to send a signal from GitLab to an application that we have built ourselves.
To implement this model, we've chose the lightweight Flask micro-framework ...