Payment QR codes have quietly replaced cash for millions of small transactions. One person shows a square, the other scans, and money moves in a second. The convenience is real, but so are the ways it can go wrong — a swapped sticker, a fake code or a payment that never arrives. Knowing the mechanics keeps both sides safe.
How Individuals and Merchants Use Them
There are two directions of flow:
- Customer-presented — the buyer shows a personal code from their wallet app and the merchant scans it;
- Merchant-presented — the shop displays a static code and the customer scans, then types the amount;
- Dynamic merchant codes — the till generates a fresh code per order with the amount and order ID already embedded.
Individuals typically use the first style; shops use the second for speed and the third when they need an exact, traceable amount.
Funds, Limits and Settlement
Money usually reaches the merchant after a short settlement window, not instantly. Daily and per-transaction limits differ by provider and by whether the account is personal or business. Portable settlement is not final money: a disputed or reversed payment can be clawed back, so treat "paid" as confirmed only once your own app shows it, not just when the buyer's screen flashes green.
Stopping Tampering and Fakes
The classic attack is simple: someone sticks their own code over yours. Defences that actually work:
- Check the name shown before accepting — the wallet displays the payee, so verify it matches you;
- Use anti-tamper stickers or a printed code on a stand that cannot be peeled and replaced quietly;
- Keep the code behind the counter where a customer cannot reach it;
- Listen for the confirmation from your own device rather than trusting a screenshot.
Reconciling Your Sales
At the end of the day, match your till and your records against the payment app's transaction list. Dynamic, per-order codes make this almost automatic because each code ties to one order; a single static code requires you to compare totals manually. If you also accept other methods, keep a note of what came in by card, cash and QR so the sums agree. Learn which other formats exist in our guide to QR code content types, and when you are ready create a QR code free with QR StarCode.