How it replaces the paper card
The mechanic is identical — a goal, a stamp per visit, a reward at the end. What changes is where the record lives. On paper, the customer holds the only copy; lose the card and the history is gone, and the business has no idea who its repeat customers are.
Digitally, the business holds the record. That means the count survives a lost phone, it cannot be forged with a borrowed rubber stamp, and for the first time the business can see how many customers are two stamps from a reward.
How a stamp gets awarded
The common pattern is a QR scan at the counter. The customer shows their member QR, staff scans it, one stamp is recorded. Bioflow works this way: the business scans from its own phone, so there is no terminal, dongle, or POS integration to buy.
The other pattern is customer-scans-business, where a code is displayed at the register. It is faster but easier to abuse, since anyone who photographs the code can claim stamps without buying anything.
What actually makes one work
A reachable goal. Ten stamps at a coffee shop someone visits twice a week is roughly a month — fine. Ten stamps at a tattoo studio is several years, and nobody finishes it.
A reward worth the trips. The reward has to cost the business less than the incremental visits are worth, and still feel like a real prize to the customer. A free drink after ten works; ten percent off after ten does not.
Enrollment that takes seconds. Every extra step at the counter loses people. If joining requires downloading an app, most customers will simply decline while there is a queue behind them.