A webhook is an automatic message sent from one system to another the instant something happens. Where an API waits for you to ask a question, a webhook flips that around: the source system reaches out to you first, the moment an event occurs.
Think of it like a doorbell. You don’t stand at the door checking every few seconds whether someone has arrived. The bell rings and tells you. A webhook is that ring: a new order comes in, a payment clears, a form is submitted, and your system is notified right away with the relevant details.
This event-driven approach is what makes real-time automation practical. Instead of polling a service every minute “is there anything new?”, you simply receive a small package of data the moment there is. Tools like n8n make it easy to catch a webhook and trigger a whole chain of actions.
The thing to plan for is what happens when your endpoint is down or slow. Most senders, like Stripe or GitHub, retry a failed delivery a few times, but they give up eventually, so a missed message can vanish quietly. A solid setup answers fast with a 200, does the heavy work afterwards, and is built to handle the same event arriving twice without doubling the result.
Security matters too, because the receiving URL is public and anyone could try to post fake events to it. Reputable services solve this by signing each message, so your code can confirm it really came from them before acting on it. The same trait that makes webhooks powerful, reacting the instant something happens, is why a careless one can do damage fast, which is why verifying the sender is not optional.
At TopDevs we use webhooks to wire systems together cleanly, so your tools react to events instantly instead of waiting on scheduled checks.
