Issue a direct merchant refund

Call POST /api/payments/captures/{capture_id}/refund from the merchant’s server with its own API key. Omit X-Merchant-Id; the credential already names the merchant that must own the capture.

Omit amount for a full refund or supply it for a partial refund. Attach an Idempotency-Key to retry the same intent safely, keep the key with the merchant’s refund record, and reconcile payment.refunded through the webhook handler. The shared refund reference holds the operation details.

Current limits

The refund operation works on a provider capture. It does not accept a checkout session, merchant order identifier, or browser callback as the money-movement target. Resolve and store the capture identifier before a refund is needed.

The direct merchant journey is complete. Use the shared reference when implementing additional operations.