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Receipt providers are actors that collect digital receipts — from merchants, POS systems, e-commerce platforms, or your own network — and deliver them to OpenCard. OpenCard attaches the receipt to the matching card transaction, extracts VAT and line items, and forwards everything to EMS apps via webhooks.

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The flow

Your job ends at the callback to OpenCard. You never talk to EMS apps directly.

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What you implement

  1. Collect receipts in your merchant network
  2. Receive match requests from OpenCard when a transaction is receiptable
  3. POST the receipt back to OpenCard when you have a match
→ How it works · Callback delivery · Payload formats

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Auth

Callbacks to OpenCard are authenticated with HMAC-SHA256: 
X-Data-Signature: HMAC-SHA256(raw_request_body, shared_client_secret)
You receive the shared secret from OpenCard during onboarding.

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Events

X-Event headerMeaning
CallbackRequestResolvedReceipt found — send receipt payload
CallbackRequestDeletedNo match / expired — send empty body
Contact support@opencard.io to become a receipt provider partner.