Webhook
An automatic notification sent from one service to another when something happens, like a doorbell that rings your code when there is news.
What It Is
A webhook is a way for one service to notify another in real time when an event occurs. Instead of your system repeatedly asking “did anything happen yet?” (which is called polling), the other service pushes a message to a URL you provide the moment something happens. When a customer makes a purchase, when a form is submitted, when a GitHub repository receives a push, the source service sends an HTTP request to your webhook URL with the details. Your receiving system (a serverless function, an n8n workflow, or any server) then processes that information and takes action.
Why It Matters
Webhooks are how modern services communicate events to each other in real time. If you are building automated workflows, webhooks are often the trigger that starts the chain. They are more efficient than polling because they only fire when something actually happens, and they are faster because there is no delay between the event and the notification. Understanding webhooks helps you design responsive systems that react to events immediately rather than checking on a schedule.
In Practice
In n8n, you create a “Webhook” node that generates a unique URL. You paste that URL into the external service’s webhook settings (Stripe, GitHub, a form builder). When the event fires, the external service sends data to your n8n URL, and your workflow processes it. A common pattern: a form submission webhook triggers an n8n workflow that enriches the data with AI and sends a personalized response via Resend.