What is a webhook?
A webhook is a URL that receives a message the moment something happens in another app. The other app pushes the event to you. You do not have to keep asking if anything changed.
In plain English
A booking, a paid invoice, or a missed call can POST the details to your workflow. That workflow might be Zapier, Make, n8n, or an agent that drafts the next step. If the URL is public, treat it like a key: do not paste it in a chat. Treat the incoming ping as untrusted mail. Check that it came from the app you expect, and check that you have not already handled that booking id. Then do one small thing. A webhook handler that also sends mail, updates the books, and texts the owner will be hard to unwind when one of those steps was wrong. Reply fast to the sender if their docs require it, then do the slow work in your own queue. A slow handler that the sender retries will do the job twice. A sluggish reply invites that replay.
How an owner would use it
Use a webhook when the other app can send events and you want the reaction in seconds. Test with one fake event. Write down what you do if the same event arrives twice.
Common mistakes
A public webhook URL is a key. Pasting it into a chat or a screenshot shares it. The other miss is assuming one event arrives once. Networks retry. If the handler charges a card or texts a customer every time the same event shows up, you will double-do the job. Write the duplicate rule before you go live. If the other app cannot push events, use polling instead of pretending a webhook exists.
A worked example
A boarding kennel
A booking pings the desk once
This is an illustration, not a customer result. The booking app sends a webhook when a stay is reserved. The workflow texts the owner the dates and the dog's name from that payload. A second copy of the same booking id does not send a second text.
Related terms
Prompts and guides
Questions owners ask
What is a webhook?
A webhook is a callback URL. Another app sends your system a message as soon as an event happens, such as a new booking or a paid invoice.
How do I use a webhook?
Create the URL in the automation tool, paste it into the sending app, send one test event, and make sure a repeat of that event does not double-charge or double-text anyone.
What is the payload?
The payload is the body of the webhook message: the fields the other app chose to send, such as a booking id and a time. Your workflow should read those fields and ignore anything it did not expect.
The automation glossary also defines Webhook. Product guides are on AI apps for business.