Backend & systems·API and interface design
instead of your client polling for changes, you POST to a URL they gave you whenever something happens.
Webhook
Also calledreverse API, HTTP callback
A server-to-server HTTP callback delivered on an event. It removes polling latency and load. It makes you a client of an endpoint you do not control, so you need retries with backoff, a signature so the receiver can verify the payload, and at-least-once semantics that receivers must deduplicate.