Offer Digital Debit® as a payment option at a barcode enabled register. The user is presented with a static or dynamic Digital Debit QR and pay an amount requested by the seller using an establish Point-of-Sale terminal. The simplest handling of Digital Debit transactions at the register is to manually record the Digital Debit transaction as a "cash" transaction upon receiving a Confirmation Panel notification. To set up an automated settlement function with your register, you will need to make a call to the PayPal API from your merchant server.
After a payer has completed a payment transaction, the Confirmation Panel of the sender and receiver device will display a PDF417 barcode of the PayPal Invoice ID. If the paying user closes the Confirmation Panel before a settlement scan can occur, and the receiver's device is not available for scan, ask the user to show their "Last Transaction" PDF417 code found in the App settings page.
Follow the 4 steps below to setup a settlement check of a Digital Debit transaction
1) Scan the PDF417 barcode from the user's device
2) Decode the PDF417 barcode to text to reveal the PayPal Invoice ID
3) Connect with the PayPal API using your developer credentials and use the captured PayPal Invoice ID and call https://developer.paypal.com/docs/api/invoicing/v1/#invoices_get and verify "status" is in the state of "PAID" or "PAYMENT_PENDING", if true then;
4) Flag the merchant server to settle the current transaction as PAID and print PayPal Invoice ID to the receipt database record. The seller should handle returns of these transactions as cash refunds.