A webhook is an automated HTTP callback that lets one application instantly send data to another when a specific event happens, without the second app needing to “keep checking” for updates.

Simple definition

  • A webhook is a user-defined URL that one app calls (usually via HTTP POST) when an event occurs, sending a small payload of data about that event.
  • Common events include things like “payment succeeded”, “form submitted”, or “file uploaded”, which then trigger actions in another system.

How a webhook works

  • You configure a destination URL in App B, then tell App A: “When event X happens, send an HTTP request to this URL.”
  • When the event fires, App A sends an HTTP request (often POST with JSON) to that URL, and App B processes the payload to do something useful (log it, update a database, send an email, kick off automation, etc.).

Webhook vs polling (why people use them)

  • With polling , App B keeps asking App A, “Anything new yet?”, which wastes resources and can be slow to notice changes.
  • With webhooks , App A pushes data to App B the moment something changes, making integrations more real-time and efficient.

Real-world examples

  • Payment platforms send a webhook to your backend when a charge succeeds, so you can activate a subscription or send a receipt.
  • Code hosting services send webhooks when you push code or open a pull request, which can trigger CI/CD pipelines or automation workflows.

Why webhooks are a big deal now

  • Modern SaaS tools rely heavily on webhooks to glue systems together in event-driven architectures, especially for automation and “no-code” workflows.
  • Because they use standard HTTP, webhooks work across many stacks and platforms, making them a flexible way to integrate apps without complex, heavy APIs.

Information gathered from public forums or data available on the internet and portrayed here.