StopKorona! was North Macedonia's COVID-19 exposure notification app.

At the height of the pandemic rush, it reached roughly 100,000 users and became the top app on the local App Store.

The app used the Apple/Google Exposure Notification system and Bluetooth-based proximity detection to privately inform users when they may have been in close contact with someone who later reported a positive COVID-19 test.

Before Apple and Google released the Exposure Notification APIs, earlier versions of the app used custom Bluetooth Low Energy (BLE) logic to detect nearby devices and record encounters. If a user reported a positive test, they could choose to upload their anonymized contact traces, and other users would be notified if a match was found. Devices emitted randomized identifiers to preserve privacy.

I worked on the app's Bluetooth logic and UI.