Webhooks have their own vocabulary: endpoints, payloads, signatures, retries, idempotency keys. Each entry gives a short definition and an example. New to the topic? Start with what is a webhook, then the webhook endpoint entry.
Basics
- Webhook endpointThe URL on your server that receives webhook requests.
- Webhook URLThe public address a provider sends webhook requests to.
- Callback URLAn address a service calls you back on: OAuth redirects, async jobs, webhooks.
- Webhook payloadThe event data in the body of a webhook request.
- Webhook listenerThe server or process that waits for and handles incoming webhooks.
Security
Delivery and reliability
- Webhook retriesRepeat delivery attempts after a failed or timed-out webhook.
- Exponential backoffRetry with growing waits, usually doubling, plus jitter and a cap.
- IdempotencyDoing it twice has the same effect as doing it once.
- At-least-once deliveryEvery message arrives, possibly more than once.
- Dead-letter queueWhere messages go after they run out of retries, so they aren't lost.
- Webhook replayResending a past webhook: recovery tool or replay attack.
- Webhook fan-outDeliver one webhook to several destinations.
Infrastructure
- Webhook forwardingReceive webhooks on a public URL and relay them somewhere else.
- Webhook gatewayA layer that receives, stores, retries and routes webhooks for you.
- TunnelA public URL for a local server, relayed over an outbound connection.
- Reverse proxyA server in front of your app that receives requests and passes them on.