Webhooks

Daybook posts signed events to the HTTPS endpoints you register, and records every delivery.

Register an HTTPS endpoint in Developers → Webhooks in the Daybook app. Daybook signs every event it sends with the endpoint's secret and records each delivery on the endpoint's page. Send test event posts a webhook.test event, so you can check your handler end to end.

The event envelope

Every event has the same outer shape.

• idstring
  Unique id: evt_ and a ULID. The same value as the webhook-id header. Use it to drop duplicates.
• typestring
  Such as webhook.test. See Event types.
• created_atstring
  RFC 3339 timestamp.
• modestring
  test from a sandbox account, live from a production account.
• dataobject
  The event's data. See Event types.

{
  "id": "evt_01JBXK8N3QZ7V2C4D5E6F7G8HJ",
  "type": "webhook.test",
  "created_at": "2026-10-29T14:31:40Z",
  "mode": "test",
  "data": {
    "endpoint_id": "whe_01JBXK4R7T2M9P5W3Y6A8C0D1E",
    "message": "This is a test event from Daybook."
  }
}

Handling events well

1. Verify the signature

   Reject anything without a valid webhook-signature. See Verifying signatures.

2. Return 2xx fast

   Daybook waits 10 seconds for your answer. Any other status, or no answer in that time, is recorded as a failed delivery. Acknowledge first, then do the work in the background.

3. Drop duplicates

   Keep the ids you've processed and skip any you've seen. A delivery that failed is tried again with the same id, so the same event can reach you more than once.