FitTrack GmbH
FitTrack — rebuilding an Android fitness app
- Platform
- Android
- Role
- Solo developer
- Timeframe
- 2025 Q2–Q4
- Kotlin
- Jetpack Compose
- Room
- Hilt
- WorkManager
The Problem
FitTrack’s Android app crashed on launch for roughly one in five users and reviews were slipping below three stars. The codebase predated Compose, state was scattered across fragments, and every release fixed one crash while introducing another.
The Solution
I rebuilt the app screen by screen on Jetpack Compose behind a stable data layer: Room for offline-first storage, Hilt for DI, and WorkManager for background sync.
Business Impact
Within eight weeks of the last migrated screen, crash-free sessions reached 99.7% and the ANR rate dropped by almost two thirds. The Play Store rating recovered to 4.4.
- crash-free users
- 99.7%
- ANR rate
- −64%
- cold start
- −38%
What I did
I rebuilt the app screen by screen on Jetpack Compose behind a stable data layer: Room for offline-first storage, Hilt for DI, and WorkManager for background sync. Each migration shipped behind the existing navigation so regressions were caught one screen at a time.
- Rewrote the 12 highest-traffic screens in Compose
- Moved workout storage from ad-hoc JSON files to Room with migrations
- Added Play Console crash and ANR alerts to the release checklist
Results
Within eight weeks of the last migrated screen, crash-free sessions reached 99.7% and the ANR rate dropped by almost two thirds. The Play Store rating recovered to 4.4 as releases stopped introducing new crashes.
Have a project in mind?
Message me on WhatsApp for a quick chat and a quote. Prefer email? hello@chikuapps.dev