"Works on My Emulator" You've built background location tracking for your Capacitor app. It works flawlessly on your Pixel. It works on the emulator. You ship it. Then the bug reports start pouring in. "Tracking stops after a few minutes." "The app dies when I lock my phone." "It worked yesterday but not today." Welcome to the world of Android OEM battery killers — where manufacturers like Xiaomi, Samsung, Huawei, and Oppo add aggressive power management layers on top of stock Android. These proprietary systems kill background services, restrict autostart, and put apps to sleep — all without telling the user or the developer. This isn't a bug in your code. It's a feature of the phone. The Problem: It's Not Android, It's the OEM Stock Android (AOSP) already has battery optimization, but it's relatively predictable. Google's Doze mode, App Standby, and Adaptive Battery follow documented rules. A properly configured foreground service survives all of them.…