In plain language
It pushes event data soon after something happens, avoiding the need for the receiving system to check repeatedly.
Example
A payment provider posts a signed “payment succeeded” event to an automation endpoint.
Related terms
API · Payload · Trigger · Idempotency
Common misconception
A webhook is not guaranteed to arrive exactly once, in order, or from a legitimate sender unless the receiver verifies it.
Implementation guidance
Use HTTPS, verify signatures against the raw body, acknowledge quickly, process asynchronously, deduplicate event IDs, and retry safely.