Webhooks API reference

Signed at-least-once event delivery with history and replay

Destinations

Ten authenticated routes create, list, inspect, update, rotate, test and delete destinations, plus read configuration and delivery history and replay one delivery. Destination filters remain inside the account's active country and family rights. Webhook destination limits are 1 for Free, 3 for Basic, and 10 for Pro.

Prediction events

Destinations with the predictions family receive prediction.event.closed when event trading stops and prediction.event.settled when the event settles or becomes void. We send each at most once per event. The body contains the event's status, never a probability or winning outcome.

Signatures and retries

Verify x-narwhal-signature as HMAC-SHA256 over timestamp + "." + raw_body. Delivery is at least once. Return a 2xx response only after durable processing, and deduplicate by delivery ID.

History and replay

Delivery history records attempt state and response status. Replay creates a new delivery for the same immutable event. Secret rotation has an overlap window so receivers can validate either advertised signature.