webhook
card-refund-updated
Sent when an individual refund changes state (for example pending to succeeded or failed).
Sent as POST with Content-Type: application/json. There is no signature header; see the Webhooks guide for how to verify. Retries: up to 6 attempts (backoff 30 s, 2 min, 5 min, 15 min, 30 min).
Return any 2xx to acknowledge. 5xx, 408, 425, 429 and timeouts are retried; other 4xx are not.