Reference
Callbacks
Callback delivery is an advanced integration pattern for handing a decision to your own endpoint.
Availability
Public webhook subscriptions, an event catalog, signing secrets, a webhook retry policy, and a webhook sandbox are not documented API v1 features.
Use the callback pattern
Use callback delivery only if your integration already requires a controlled callback endpoint. This is separate from Script Tag events raised in the browser.
Choose the standard flow otherwise
For a new backend integration, request a placement and pass a filled response to the hosted renderer.
Need help with your integration?
Share the affected endpoint, request ID, and the behavior you expected. Leave out keys and user content.