http
POST /api/payments HTTP/1.1
Host: payment.example.com
Content-Type: application/json
{"amount": 99.99, "currency": "EUR", "payment_method": "sepa"}
HTTP/1.1 202 Accepted
Location: /api/payments/pmt-xyz
Content-Type: application/json
{"payment_id": "pmt-xyz", "status": "pending", "webhook_url": "https://merchant.com/webhooks/payment"}