Duper

Lost your phone? Send it "duper". Why "Duper"? It's French verlan (backwards slang) for "perdu" — meaning "lost". Reverse the syllables: du-per. The app that finds what's lost, named after being lost. Duper lets you remotely control your Android phone using SMS commands. It has no account, server, tracking SDK, or internet permission. Secrets, settings, command history, and location data stay on the device and are excluded from Android backups and device transfers. Send "duper ring" to make your phone ring with the flashlight blinking. Useful when you've lost your phone nearby. Device and Do Not Disturb policies may limit alerts. Send "duper locate" to receive GPS coordinates by SMS at regular intervals. Useful in an emergency or when you lend your phone to someone. Features: • Ring with flash, bypasses silent mode • GPS location tracking via SMS • Both modes stop when the phone is unlocked • Configurable command prefix, optional Ring password, Locate secret, duration, and interval • Custom ringtone support • Works entirely offline over SMS • No account, no cloud, no tracking The Camera permission is used only to control the device torch during a ring alert. Duper does not capture photos or video. The Vibration permission is used only for ring alerts. Location uses location permissions, including background location when the app is closed. The optional ADB-only WRITE_SECURE_SETTINGS permission lets Duper attempt to enable Android location services when they are off; it is not needed when location services are already enabled. Ring and Locate are disabled by default. Ring can use an optional password and optional SMS confirmation; Locate requires its own secret and sends SMS responses. The app requests only the permissions needed when you enable each mode. For privacy, remote commands run only while the phone is locked and stop when it is unlocked. Note: On Android 13+, you may need to allow restricted settings once in the app settings before granting permissions. Open source under GPL-3.0.