Retailer Message Flows
From a retailer perspective the QR payment flow comprises of the following operations:
- Requesting and displaying a QR code
- Making a payment authorisation request based on this QR code
- Finalising or reversing this payment
Request a QR Code
The message flow to request a QR code works in the following manner:
- The retailer requests a QR code to be generated using the getQrCode operation.
- The QR server returns a QR code containing a unique transaction ID (
tranId). For the the structure of this QR code please see the Advanced Topics section.
- The retailer displays the above QR code to the customer allowing the customer to begin the payment journey by scanning this QR code with their mobile device.
Request a payment
The payment flow is dual message and comprises two messages:
- A payment authorisation request (
PaymentRequest), which will request the funds to be reserved for tender by the Partner. This request contains the unique ID encoded in the QR code and will be used to match this
PaymentRequestto the QR scan.
- One of the following two advice messages, which will be sent “offline” and subject to store-and-forward (SAF; see Advanced Topics):
- A finalisation advice (
ConfirmationAdvice), which signifies to the Partner that the tender was successful and the funds should be withdrawn.
- A reversal (
PaymentReversal), which signifies that the tender was not completed and that the reservation on the funds should be removed.
- A finalisation advice (
It is important to note that the
PaymentRequest should always be sent upstream before the QR code has been displayed to the customer for scanning. This is to prevent
creating a window in which it is possible for the customer to scan the QR code before the
PaymentRequest is sent. In this case it would not be possible to match the
PaymentRequest to the QR scan and hence the tender will fail.
Below is a flow depicting the scenario where a
PaymentRequest arrives after the QR code has been scanned.
Tender Voids and Timeout Reversals
As mentioned above, a payment authorisation (
PaymentRequest) may be reversed or “cancelled” by a
PaymentReversal should be sent in either of the scenarios below:
- To void an otherwise successfully processed payment authorisation. This may be required for a number of scenarios, for example the customer has opted to not continue with the tender, the POS malfunctioned or the basket has been voided by the cashier.
- No response to a
PaymentRequestwas received and the state of the transaction upstream is unknown. In this scenario a
PaymentReversal, as a “Timeout Reversal”, should be sent to ensure that it is safe to proceed as if the transaction has not gone through. A
PaymentReversalwill be subject to SAF, thus it is guaranteed that this transaction will eventually be reversed.
In both case above, reversals are intended to correct a system issue or a cancelled transaction, and thus will not be used as a general purpose refund mechanism. Customer refunds and return of goods are out of scope of this document.
The full flow for a TimeoutReversal is as per the below diagram.