PSM API Server (Android)

Full-featured SMS/MMS HTTP API server that runs entirely on an Android device.

Highlights

• Works on Android 4.3 (API 18) – last version that still allows 3rd-party MMS access.
• HTTP server (NanoHTTPD) exposed on the device IP (default port 8080).
• Send / receive SMS & MMS, statistics, contact import, live uptime counter.
• Auto-start at boot, background service with ongoing notification.
• Built with Kotlin + AndroidX, but trimmed to stay compatible with API 18.

Core API Endpoints

Method	Path	Description
GET	/health	Quick health-check JSON {status:"healthy"}
GET	/docs	HTML documentation page (device browser)
GET	/statistics	JSON with server + usage stats
GET	/uptime	{uptime_minutes:123}
GET	/messages?phoneNumber=&type=&limit=	List messages, optional filters
GET	/phone-numbers	List phone numbers that have message history
GET	/contacts	List phone numbers imported from device contacts
POST	/sms/send	Body {phoneNumber:"+123", message:"hi"}
POST	/mms/send	Multipart form: phoneNumber, message, attachment

See /docs while the server is running for examples.

Building the App

Tool	Version
Android Studio	Hedgehog / Electric Eel+
Gradle	7.6.1 wrapper (bundled)
Android Gradle Plugin	7.4.2
compileSdk / targetSdk	33
minSdk	18
JDK	11 (set in Android Studio: Preferences ▶ Build Tools ▶ Gradle JDK)

Steps:

1. Open project in Android Studio.
2. When prompted, allow it to download SDK Platform 33 (build only).
3. Ensure File ▶ Project Structure ▶ JDK points to a JDK 11 install.
4. Run ▶ app – the APK installs on any device/emulator running API 18 +.

Runtime Permissions

On first launch the app requests SMS / MMS / storage / network permissions. After granting once they are remembered; the prompt is suppressed on subsequent launches.

UI Overview

• Main screen – server status, uptime, IP address, quick nav buttons.
• Settings – change port, toggle auto-start, scan contacts, restart server.
• Chat Overview – list conversations; tap to see message history.

Customising

• HTTP port is saved in Settings. All endpoints automatically use the new port after restart.
• Colors / typography live in res/values/colors.xml and layout card styles.

Limitations & Notes

• MMS sending on API 18 is best-effort; attachment support depends on the device.
• On very old devices vector drawables aren't supported; notification icon uses PNG.
• OpenGL/EGL warnings seen in logcat on emulators are harmless.

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Released under MIT license. Enjoy hacking your retro Android SMS gateway!
Please star the repo if you find it useful.