Personal
Sep 2022
One Wallet, Many Cafes
Digital stamp cards that small cafes can set up in minutes.
Digital stamp cards that small cafes can set up in minutes.
This project created a simple wallet app that stores loyalty cards from many independent cafes in one place. It includes a companion flow for merchants, a light weight web console for owners, and a privacy first data model. Customers collect stamps with a quick scan and redeem rewards without paper. Cafe staff issue stamps in a few seconds at the counter. Owners see basic insights that help them tune offers without hiring a data team.
Paper cards get lost. They invite fraud and they do not tell owners what works. Each cafe solves loyalty in its own way, which splits attention and creates clutter in the customer’s wallet. Small shops want digital loyalty but fear complexity, long contracts, and high fees. Staff have no time to learn a heavy tool during the morning rush, so any solution must be obvious at a glance and fast under real world conditions.
I interviewed cafe owners, managers, and baristas across different neighborhoods, then paired those insights with short intercept chats with regulars at the till. I mapped the visit from order to pickup and marked the moments where a stamp fits without slowing service. Lo fi sketches explored three stamp models, merchant scans customer, customer scans merchant, and code entry on receipt. I built mid fidelity prototypes and tested them in three pilot cafes during both quiet and peak hours. I iterated on speed, legibility, and recovery for offline moments. I wrapped the patterns in a small design system with tokens and components so future features could ship consistently.
One challenge: Prevent abuse without point of sale integration, keep the stamp flow under five seconds, and make the setup friendly for owners who do not live in tech. The system needed trust for both sides and a path that works with spotty connectivity.
Time to issue a stamp at the counter, median 4s · First month repeat visit rate, up 24% among enrolled customers · Reward redemption rate, 9% to 17% · Lost or forgotten card incidents, effectively zero · Support requests per cafe per week, down 41% after the second release ·Opt in to share contact info, 72%
Enrollment became tap and join. Customers scan a table tent code or a sticker at the register, the app creates a card for that cafe and shows the first empty stamp slot. Stamping runs in two modes selected by the cafe. In scan customer, the barista scans the customer’s in app code with the merchant camera and the app adds a stamp instantly. In scan merchant, the customer scans a rotating merchant code after paying and receives the stamp. A rolling code scheme and per shift limits reduce fraud while keeping the flow fast. Redemption shows the reward value and any rules up front. The barista confirms with one tap and the card resets. The wallet organizes many cards by proximity and visit recency, which keeps the current cafe at the top. Notifications remain gentle. The app nudges only on nearby cafes where a reward is close. The owner console offers three basics, active cards, stamp and redemption counts, and a simple repeat visit view. Microcopy uses cafe language so staff can learn it in minutes. Accessibility follows WCAG AA with clear focus order, large tap targets, and readable QR guidance. The system works offline for short periods and syncs when the device reconnects. No personal data is required to collect stamps, contact info is optional and explains the benefit clearly.
The best time to stamp is while the drink is being made, not during payment. Staff preferred scan customer during the morning rush because the barista controls the timing and the phone stays behind the counter. Customers liked seeing progress in the wallet immediately after ordering. Anti fraud features worked when they stayed invisible. A rotating code and per shift limits were enough, heavy verification was not needed and hurt speed. Owners wanted simple goals instead of complex analytics. Cards issued, stamps this week, and rewards redeemed covered most decisions. Optional account creation after the first reward outperformed early sign up, which kept the app friendly for casual users.
This redesign turns scattered paper cards into a single wallet that respects the pace of small cafes. Setup is quick. Stamps are fast. Rewards are clear. Owners get simple levers they can actually use. The foundation supports cross cafe promotions, seasonal rewards, and partnerships with roasters, which opens a path for steady growth without adding friction for baristas or customers.