webhook

A webhook is a push-based HTTP callback that triggers real-time data transfers between systems when a specific event occurs.

Think of webhooks as reverse APIs: instead of your server polling for updates every 30 seconds, the source system (like Stripe, GitHub, or Shopify) pushes a JSON payload directly to your endpoint the moment an event triggers. When a customer completes a checkout or a developer pushes code to a main branch, the source sends an HTTP POST request containing the relevant data. This architecture eliminates unnecessary network overhead and ensures your application reacts instantly (sub-second latency) to external state changes. It is the standard protocol for building reactive, event-driven integrations across the modern web stack.

https://webhooks.pb.dev