I need an Android APK that can sit quietly in the background on any device—from the oldest handset still running to the latest Android release—and forward every single incoming SMS. Each message has to be pushed two ways: first to another mobile number of my choosing, and second to my Firebase Realtime Database in near-real time. Reliability is everything. The service should automatically restart after a reboot, survive battery-optimization and manufacturer kill policies, and remain active even when the screen stays off for days. As soon as the phone powers back on, the app must revive itself and continue forwarding without any user interaction. Because I am using Firebase Realtime Database, build in the necessary authentication and structure the data so I can filter by device ID and timestamp later. I will provide the database URL and credentials; you wire up the rest. Deliverables • Release-ready APK plus full, well-commented source code • Clear setup notes: required permissions, steps to add my Firebase keys, and how to whitelist the app from battery optimization on common OEM skins • A quick test plan showing the reboot, airplane-mode, and doze-mode scenarios you ran to confirm uninterrupted forwarding If you already have experience bypassing Doze, App Standby, and background execution limits, let me know—those skills will be key to getting this accepted.