Event Payload

Envelope

Every Medallion webhook is delivered with the following JSON body:

{
  "type": "payer_enrollment.request.in_progress.v1",
  "data": {
    ...event-specific fields...
  }
}

Field	Type	Description
`type`	string	The event type name
`data`	object	Event-specific payload — see the event catalog for the event type

Delivery metadata is carried in HTTP headers, not in the JSON body:

Header	Description
`webhook-id`	Unique event ID. Use as a deduplication key
`webhook-timestamp`	Unix timestamp of the delivery attempt
`webhook-signature`	HMAC-SHA256 signature. Verify before processing

Event type names follow the pattern:

{domain}.{resource}.{description}.{version}

Example: payer_enrollment.request.in_progress.v1

Component	Description
`domain`	Product area (e.g. `payer_enrollment`)
`resource`	Entity being described (e.g. `request`)
`description`	What happened (e.g. `in_progress`, `blocked`, `terminal`)
`version`	Schema version (e.g. `v1`)