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How to build a resilient activity tracker with Expo — Expo blog
A detailed engineering writeup describes building a resilient walking-activity tracker in Expo/React Native that survives app kills, backgrounding, and GPS noise. The team uses Expo TaskManager to run background GPS tracking outside the React lifecycle, applies a multi-gate Kalman filter pipeline (accuracy, speed, outlier, and Doppler-speed integration) to eliminate vehicle-distance inflation, and layers persistence across Zustand, AsyncStorage, and Supabase with monotonic merge logic to avoid write races between the background task and foreground store. It covers Android OEM battery-killer mitigations, iOS background location edge cases since iOS 16.4, a custom Kotlin Expo Module for Android step counting via STEP_COUNTER, and a three-way recovery status (found/not-found/unreachable) to safely resume sessions after crashes or offline relaunches.
Source: https://expo.dev/blog/how-to-build-a-resilient-activity-tracker-with-expo. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.
