Webhooks
Webhooks notify your service when workspace events happen, so it can react without polling: start a job, sync another tracker, send a notification, or fetch more context with the REST API.
Create a webhook
Workspace admins create webhooks under Settings → Apps. Add an HTTPS endpoint, set or generate a verification key, choose the events to receive, and verify the endpoint. Recent delivery attempts are recorded with status codes and error types.
Delivery model
Events are CloudEvents JSON: stable event metadata plus a data object with the changed resource. Current event names are in the API reference.
Delivery uses bounded retries: one immediate retry, then retries after roughly one minute and five minutes before stopping for that event.
X-One-Webhook-Key is a shared verification key, not a body signature. Store the same value in your receiver and compare it before processing the event.
Verification calls the endpoint from One Horizon infrastructure. It sends HEAD first and falls back to GET when the endpoint returns 405. Event delivery uses POST.
Return a 2xx response after the event has been accepted. Use the event ID for idempotency so retries do not create duplicate side effects.
Building an agent with webhooks?
Cloud agents can use webhooks as notification that agent work may be available. A webhook only wakes up the service; the agent still needs to fetch and claim the session before running. Build a Cloud Agent covers the full flow from notification to claim to completion.