What is a webhook?

Webhook: definition and principle

A webhook is often called a “reverse API.” With a classic API, a program regularly checks whether there is anything new. A webhook works the other way around: the source system reports on its own as soon as something happens.

Technically, a webhook is usually an HTTP POST request with the event data in JSON format. The receiving system provides a URL for this—the so-called endpoint—and processes the incoming messages.

Many popular services offer webhooks, including payment providers such as Stripe and PayPal, store systems such as Shopware and Shopify, and code platforms such as GitHub.

How a webhook works

First, you specify in the source system which events should trigger a message and which address it should be sent to. When the event occurs, the system sends the data. The recipient confirms receipt with a status code and triggers the next steps.

Typical use cases in day-to-day business:

• Payment provider reports “payment received” to the online store
• Store reports “new order” to the inventory management system or shipping service
• Website form passes an inquiry to the CRM
• Code platform reports a change to the CI/CD pipeline

Benefits and limitations of webhooks

Webhooks work in near real time and save resources because no constant checking (polling) is required. This makes them well suited for automating processes across multiple systems.

Because the recipient offers a publicly accessible address, it must verify incoming messages—typically using a signature with which the sender proves its authenticity. Processing should also be able to cope with a message arriving late, twice, or again after an outage.

• Real time instead of delayed syncing
• Low load on both systems
• HTTPS and signature verification are a must
• Handle retries and duplicate deliveries cleanly

Real-world example: forwarding orders auto­mati­cally

An online retailer receives orders through its store. Until now, they were collected each morning and transferred to the shipping provider by hand. With a webhook, the store immediately reports each new order to a small middleware that creates the shipping label and writes the tracking number back. Manual retyping is eliminated, and customers receive their shipping confirmation faster.

Webhooks make sense wherever an event should promptly trigger an action. Nano Concepts sets up webhook integrations, secures them, and builds in logging so you can always trace which message was processed when.