The flow
Your job ends at the callback to OpenCard. You never talk to EMS apps directly.What you implement
- Collect receipts in your merchant network
- Receive match requests from OpenCard when a transaction is receiptable
- POST the receipt back to OpenCard when you have a match
Auth
Callbacks to OpenCard are authenticated with HMAC-SHA256:Events
Contact support@opencard.io to become a receipt provider partner.

