Glossary
Webhook
A push notification pattern where an external system POSTs to your endpoint when an event occurs.
A webhook is an outbound HTTP push notification — when a defined event happens in System A, it POSTs a payload to a URL you've registered, instead of you polling A for changes. In Microsoft 365, webhooks appear as Microsoft Graph change notifications (subscribe to changes on mail, files, users, calendar events; Microsoft POSTs your endpoint when they change), Teams outgoing webhooks (a channel posts your endpoint when someone @mentions a bot), and Teams incoming webhooks (your system POSTs JSON to a channel URL to deliver a card). Webhooks are the foundation of event-driven integrations and far more efficient than polling for systems that need to react quickly to changes.