Partial Authorization

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Partial Authorization is a feature that allows a transaction to be partially approved when the cardholder's available balance is less than the requested amount. Instead of declining the entire sale, the payment network authorizes the maximum amount available on the card.

This feature enhances customer experience and allows POS to process payments more smoothly. It has to be enabled during the provisioning stage.

API Implementation and Logic

When a card is used that doesn't hold the full requested amount, the processing is managed as follows:

  1. Request: The POS sends a standard /payment request with the total RequestedAmount (e.g., €100.00).

  2. Authorization: The card network approves the transaction for the available amount (e.g., €40.00).

  3. Response: The final PaymentResponse returned to the POS signals this status through the RTRResultType field (Partial).

  4. Action: The POS must identify the authorized amount to calculate the remaining balance.

Key Data Fields for Handling Partial Payments

The POS application uses the following fields in the final PaymentResponse to manage the remaining balance:

Component ObjectData FieldExpected ValuePOS Action
PaymentResponse.ResponseResult

"Partial"

Mandatory Check: The POS uses this value to confirm the transaction requires a secondary payment method.
PaymentResult.AmountsRespAuthorizedAmount

The amount actually approved by the issuer (e.g., 40.00).

The POS uses this field to know what has been paid. The remaining balance is calculated by subtracting this value from the original RequestedAmount.
AmountsRespCurrency

The currency of the authorized amount.

Ensures the calculation is performed in the correct currency.

POS Responsibility

The ECR (POS) system has the following responsibilities when receiving a "Partial" result:

  1. Calculate Remaining Balance: Subtract the AuthorizedAmount from the original RequestedAmount.

  2. Prompt Customer: Ask the customer for a complementary payment method (cash, another card, etc.) to cover the remaining balance.

    1. Customer pays with POI: initiate a new POST/payment request for the calculated outstanding balance.

    2. Customer pays with an alternative payment method: no action required

    3. Customer wants to cancel partial authorized amount: initiate a POST /reversal to uto undo the authorized payment