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Amount-locked vs open QR codes
Kit Pay merchants can show two kinds of QR code: one locked to an exact amount, one open for the customer to fill in.
Both kinds of merchant QR code are signed and verified; the difference is what they say about the amount. One kind locks it. The other leaves it open for the customer to enter. Choosing well between them is a small decision that removes a whole class of counter disputes.
Amount-locked codes
An amount-locked code is issued for one specific payment: this amount, this merchant, its own validity window. When the customer scans it, the amount is already fixed inside the signed code — they review it and approve, and a payment that does not match what the code was issued for is refused outright. Nothing to mistype on either side of the counter.
- Best for: a specific bill — the restaurant table, the finished repair, the agreed price.
- The lock is enforced, not decorative: a mismatched amount fails verification rather than going through wrong.
- Each code belongs to one payment, so a paid code does not linger as a way to pay twice.
Open codes
An open code is reusable: it identifies your merchant account, and the customer enters the amount when they scan — an amount is required before anything proceeds. It is the laminated code taped by the till, serving every sale without a fresh code per customer.
- Best for: a steady counter with varying totals — the shop, the stall, the salon.
- Say the total clearly and let the customer enter it; their review screen shows your business name and their entered amount before they approve.
- The customer's approval is theirs: you see the result in your records rather than taking their word for it. Business records shows where to look.
Frequently asked questions
Customer says they paid, but I see nothing — which code lies?
Neither. The truth is your merchant records: a completed payment appears there, and no entry means no payment reached you, whatever a screen on someone else's phone appears to show.
Can I keep using one amount-locked code for the same-priced item?
An amount-locked code belongs to one specific payment with its own validity window, not to a price. For a fixed-price counter, an open code plus the spoken total does the job continuously.