Case study
Laburo
Smart workforce management
Mobile app for workforce attendance management with QR check-ins, geolocation, and biometric verification. Integrated with a NestJS API.
Role
Fullstack development: mobile app (React Native / Expo) and backend (NestJS).
Stack
Companies needed a reliable way to track staff clock-ins and clock-outs without manual spreadsheets or dedicated attendance hardware.
Dynamically generated QR clock-in, additionally validated against a geographic radius via expo-location, to prevent clock-ins from outside the workplace.
Clock-in confirmation using whichever biometric the user already has set up on their device (fingerprint or face), without capturing or storing any biometric data of its own.
JWT authentication (access + refresh token) with bcrypt password hashing, using guards and a custom @CurrentUser decorator in NestJS.
Session persistence with expo-secure-store instead of AsyncStorage, to avoid storing tokens in plain text on the device.
The biggest challenge was designing location validation that tolerated normal GPS drift without allowing fraudulent clock-ins from outside the office — solved with a per-company configurable radius instead of requiring an exact point.
Working with native permissions (camera, location, notifications) in Expo forced me to design for error UX: what to show when a user denies a permission, and how to gracefully degrade functionality instead of blocking the rest of the app.