Payment links at the till (QR, SMS, email)

When the customer has no card with them, or pays later: the till shows a QR code or sends a payment link by SMS or email, the customer pays on their phone (card, MobilePay, online bank), and the sale completes automatically on the till when the payment is confirmed. Also handy for phone orders and deposits. Uses the shop's own online payment provider; the shop keeps its own contract and fees.