What is Webhook?
A mechanism for one system to notify another system in real time when an event occurs.
Definition
A webhook is an HTTP callback — a way for one system to push real-time notifications to another when something happens. The sending system makes an HTTP POST request to a configured URL (the 'webhook endpoint') with event data whenever the trigger event occurs. Webhooks enable event-driven architectures: instead of repeatedly polling an API to check for changes, you register a webhook and get notified automatically.
Example
Stripe sends a webhook to your application every time a payment succeeds, fails, or a subscription is created. An AI agent can use webhooks as triggers — when Stripe fires `payment.failed`, the agent automatically sends a customer notification and creates a support ticket.
Webhook vs api: What's the difference?
A mechanism for one system to notify another system in real time when an event occurs.
An API is pull-based — you ask for data when you want it. A webhook is push-based — the system notifies you automatically when something happens.