Android · Security · Mobile
June 2026
Live on Play Store
PhoneGuard —
Your Device Never Sleeps
Enterprise-grade anti-theft and remote device recovery suite for Android. Built with a decoupled Flutter + Native Kotlin architecture that operates even when the app is terminated, the screen is off, or cellular data is disabled.
2
SMS Detection Layers
3
GPS Fallback Tiers
0s
Boot → Service Startup
Live
Google Play Store
Flutter 3.x
Kotlin
CameraX
Firebase Firestore
Firebase FCM
Hive
Device Admin API
SmsManager
FusedLocationProvider
Provider
Next.js Dashboard
The Problem
Standard Anti-Theft Apps Fail When You Need Them Most
Most "Find My Device" apps rely on a continuous data connection, an open Google account session, and location services being enabled — conditions that a thief will disable within seconds. PhoneGuard was built to operate under adversarial conditions.
Data Connection Dependency
Standard tracking apps fail if cellular data or Wi-Fi is disabled. Thieves know this. PhoneGuard uses SMS triggers to bypass internet dependencies entirely.
GPS Can Be Disabled
Thieves immediately disable location services. PhoneGuard implements a 3-tier GPS fallback: High-accuracy → Network/Wi-Fi Triangulation → OS Cached Last Location.
SMS Interception by Other Apps
Many third-party messaging apps intercept and consume SMS broadcasts (abortBroadcast()). PhoneGuard implements a ContentObserver on the inbox to read triggers directly from device storage as a fallback.
Lock Screen Bypass
Stock Android lock options can sometimes be bypassed. PhoneGuard integrates with the Android Device Admin API to lock the screen instantly and enforce protection at the OS level.
No Visual Evidence
Standard apps don't capture who is using your phone. PhoneGuard silently captures a front-camera photo on every failed unlock attempt and uploads it to your private cloud dashboard.
Core Features
Seven Layers of Protection
-
Intruder Selfie (CameraX)
Silent front-camera photo on failed unlock attempts. No sound, no preview. Uploaded to private dashboard as Base64 WebP. -
SIM Change Alert
Instantly detects SIM swap, sends the thief's new number to all trusted contacts via SMS. Police reporting made easy. -
Remote SMS Control Center
Send secret trigger keywords from any phone. Commands: siren alarm (overrides silent mode), remote lock, GPS coordinates reply. -
Web Dashboard (Vercel)
Live map view, remote alarm/lock triggers, intrusion photo gallery. Next.js + Firebase. No SMS needed from the dashboard.
-
Device Admin API Lock
Prevents uninstallation by a thief. Calls DevicePolicyManager.lockNow() to instantly lock the screen at OS level. -
Dual-Layer SMS Detection
Layer 1: BroadcastReceiver (priority 1000). Layer 2: ContentObserver on SMS DB. If any app blocks the broadcast, the observer fires as fallback. Zero command drops. -
3-Tier GPS Fallback
Tier 1: FusedLocation high-accuracy. Tier 2: Network/Wi-Fi/Cell triangulation. Tier 3: OS cached last-known location. Always reports something. -
FCM Push Commands
Firebase Cloud Messaging delivers commands even when app is terminated. FcmCommandHandler executes alarm/lock without any SMS needed.
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