Yokla
A mobile attendance app based on QR codes that refresh during class.
In Yokla, the teacher starts an attendance session and displays a QR code that changes every 10 seconds. A previously captured or shared code therefore becomes invalid shortly afterwards.
- Students scan the QR code to check in and can view their attendance history.
- Teachers start sessions and view attendance by course.
- Administrators manage users, courses and class sections.
Authentication and data are stored in Firebase. I use Firestore Security Rules to control data access, while operations such as session-token validation run in Cloud Functions rather than on the client.