A webhook is an HTTP request that one system sends automatically to a URL of another system when an event occurs. In SEO monitoring, webhooks forward alerts to chat tools, ticket systems or automation platforms.
How does a webhook work?
The receiving system provides a URL and, if the sender allows it, selects which events it wants. When one of these events happens, the sending system makes an HTTP POST request to the URL with data about the event, called the payload. Red Hat describes webhooks as “reverse APIs” or “push APIs”, since the server starts the communication. GitHub calls this a way to subscribe to events and receive data whenever they occur.
How does a webhook differ from an API request?
With a regular API, the client asks for data and repeats the request to learn about changes, which is called polling. Webhooks avoid the repeated requests, because data arrives when something happens. Zapier compares polling to repeatedly knocking on a door to ask whether anything is new.
Example
Invented example of a payload that a monitoring tool might send when a check fails:
{
"event": "alert.created",
"severity": "critical",
"url": "https://www.example.com/products/",
"message": "Page returns status 500",
"timestamp": "2026-10-06T07:42:00Z"
}
An automation service receives it and posts a message in the team’s chat. The field names differ between tools. The sender and payload in this example are made up.
Common mistakes
- Exposing a receiving URL without any check of the sender. Many systems offer a secret or signature for this, and the receiver should verify it.
- Not answering quickly with a success status, so the sender repeats the delivery.
- Not handling duplicates when the same event arrives twice.
Sources
- What is a webhook? – Red Hatredhat.com
- About webhooks – GitHub Docsdocs.github.com
- What are webhooks? – Zapierzapier.com
- Webhook – Wikipedia (secondary)en.wikipedia.org
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