What Android OEMs do to background apps, and the 11 layers I built to survive it

I spent over a year building a safety monitoring app that runs 24/7 on elderly parents' phones. If it gets killed, nobody gets alerted when something goes wrong. That constraint forced me into the deepest, most frustrating corners of Android background execution. This article covers what I learned about how Samsung, Xiaomi, Honor, OPPO, and Vivo actively kill background apps, why the standard Android approach is nowhere near sufficient, and the 11-layer recovery architecture I ended up building. I will also cover two related problems that surprised me: GPS hardware that silently stops working, and accelerometer data that lies about its age. 126,000 lines of Kotlin, 125+ versions, solo developer. The app is called How Are You?! — it learns an elderly person's daily routine over 7 days, then monitors around the clock and emails the family if something seems wrong. But this article is about the engineering, not the product. The problem: Android wants your app dead Stock Android already ma