Webhook
An automated HTTP callback that sends real-time data from one application to another when a specific event occurs.
Definition
A webhook is a way for one application to notify another that something happened, in real time. Rather than repeatedly asking a server “did anything change?” (polling), a webhook lets the server push a notification to a URL of your choosing the moment an event fires.
Why it matters
Webhooks make integrations lightweight and responsive. Polling wastes resources and introduces lag; webhooks are event-driven and instant. They’re the foundation of modern automation tools and allow loosely coupled systems to react to each other without tight integration.
Example
When someone makes a payment through Stripe, Stripe sends a webhook to your server so you can immediately update the user’s account. GitHub sends webhooks when code is pushed, triggering CI/CD pipelines. Zapier and Make rely heavily on webhooks to connect apps.