# What is a webhook?

> A webhook is an automatic HTTP request, usually a POST, that a third-party service sends to a URL on the merchant site when a specific event occurs, without any action from the user.

- Source canonique : [https://allaux.fr/en/glossaire/webhook](https://allaux.fr/en/glossaire/webhook)
- Langue : EN
- Dernière mise à jour : 2026-09-30

## The most common use case

During a payment, the customer often leaves the site to complete the transaction on the payment gateway's page. Once payment is confirmed, the gateway sends a webhook to a dedicated URL on the merchant site to signal that the transaction succeeded. It's this webhook, not just the browser redirect, that reliably confirms the order, even if the customer closes their browser before returning to the site.

## When things go wrong

If the webhook doesn't reach the site, for example because of an incorrect URL, a temporary outage or a blocking firewall, the notification never arrives. The order stays stuck at “pending” status in the back office, even though the payment was actually charged on the customer's side.

## A stuck order isn't necessarily cancelled

> Before cancelling an order stuck at “pending”, it's worth checking on the payment gateway side whether the payment was actually confirmed: the problem is often a webhook that failed to reach the site.

## FAQ

### Why does an order stay at “pending” when the customer has already paid?

Most often because the webhook sent by the payment gateway didn't reach the site, for example due to a misconfigured URL or a temporary server outage.

### Is a webhook the same thing as an API?

No. An API is actively queried by a system requesting information; a webhook is sent automatically by the originating service when an event occurs, without any prior request.

### How can you check that a webhook is working correctly?

By checking the notification history in the gateway's interface, and verifying that the URL configured on the site is publicly accessible.