Digital Loyalty Card with QR Code for a Coffee Shop or Salon

We run a small offline point of sale — think coffee shop or a hairdressing salon — and paper punch cards are getting lost, torn, and hard to track. We want to switch to a digital loyalty card built around a QR code that lives right next to the till. A customer shows the code on their phone, the cashier or a simple scanner reads it, and a visit or a purchase amount is added to their account automatically, without anyone typing numbers into a spreadsheet.

The card itself should be something a client can save straight into their phone's wallet app, so they don't need to install anything extra or remember a login. After a set number of visits or a spending threshold, the system should mark a reward as earned and let the staff at the register know it can be redeemed on the spot. We'd also like a simple admin view where we can see how many active cards exist, how often they're used, and adjust the reward rules without calling a developer every time.

We're open to different technical approaches — a lightweight web app, a scanning terminal, or an admin panel that ties into whatever till we're already using — as long as it works reliably on an ordinary phone camera and doesn't require expensive hardware. Please describe your experience with similar loyalty or punch-card systems and how you would structure the QR logic and wallet integration.

What matters to us:
— reliable QR generation and scanning, even on older phones
— automatic visit or purchase counting with no manual entry
— card storage in a standard phone wallet
— a simple, fast scanning flow for staff at the register
— basic statistics and reward-rule settings for the owner