What is a webhook?

A webhook is one app sending a message to another app the moment something happens, so the second app does not have to keep checking.

7 min read min de lecture

~$ man webhook

What is a webhook?

Web Dev & SaaS gneurone encyclopedia
A webhook is one app sending a message to another app the moment something happens, so the second app does not have to keep checking.

definition

A webhook is an automated HTTP POST request sent to a predefined URL when a specific event occurs in the source application.

It enables event-driven communication instead of clients repeatedly polling an API for updates.

Webhooks are widely used for notifications, data synchronization, and connecting services such as payment gateways or version control systems.

A webhook works like a doorbell: when a package arrives the bell rings once to tell you, instead of you opening the door every few minutes to look outside.

key takeaways

  • Webhooks deliver data via HTTP callbacks to a registered endpoint URL.
  • They eliminate constant polling and reduce server load and latency.
  • Payloads usually contain event details in JSON format.
  • Endpoints must be publicly reachable and able to handle retries.
  • Verification uses shared secrets or digital signatures to confirm authenticity.

the 2026 job market

By 2026 event-driven architectures and SaaS integrations continue to expand, increasing demand for backend and integration engineers who can design, secure, and maintain reliable webhook systems across distributed services.

Backend Developer · $92,000-$138,000 / CAD 78,000-116,000 / £52,000-£82,000Integration Engineer · $88,000-$132,000 / CAD 74,000-112,000 / £49,000-£78,000DevOps Engineer · $102,000-$155,000 / CAD 86,000-128,000 / £57,000-£88,000

frequently asked questions

How does a webhook differ from an API call?

An API call is initiated by the client to fetch data on demand. A webhook is initiated by the server to push data automatically when an event occurs.

What happens if a webhook delivery fails?

Providers typically retry the request several times using exponential backoff. Applications should also implement idempotency keys to process duplicate deliveries safely.

How can I test a webhook locally?

Use tools such as ngrok or localtunnel to expose your development server through a public URL that the webhook provider can reach.

Which programming languages are commonly used with webhooks?

Any language with an HTTP server works; Node.js, Python with Flask or FastAPI, and Go are frequent choices for handling incoming webhook payloads.

courses to go further

Python Requests APIs
30 lessonsPython Requests APIsComing soon
$ cat ./full-guide.mdPython Requests APIs expliqué simplement (avec schémas et vrai code)read the guide →

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Auteur(s)

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REHOUMA Haythem

Haythem Rehouma est un ingénieur et architecte IA et cloud, formateur et enseignant technique, avec un profil orienté IA médicale, AWS, MLOps, LLM/RAG et vision par ordinateur.