Relay Android App

Relay is an Android app for cross-device notification and message relay, supporting a custom protocol for real-time communication with desktop clients.

Features

• Notification mirroring from Android to desktop
• Actionable notifications (reply, action buttons, dismiss)
• Bidirectional protocol with length-prefixed JSON messages

Getting Started

Install the APK: Download the latest APK from the Releases page and install it on your Android device.

Or Build from source: Clone this repository and build the app using Android Studio or Gradle:

./gradlew assembleDebugOptimized

Then install the generated APK on your device.

First-time setup:

• Open the Relay app after installation.
• Grant the required notification permissions when prompted.
• Go to your device's App Settings for Relay → Battery optimizations → Allow unrestricted usage (to ensure background operation).
• Make sure the app server is running.
• You can now close the app; the Relay service will keep running in the background and forward notifications to connected clients as long as permissions are granted.

Cross-Platform Desktop Client

A cross-platform desktop client implementation is available at:

• https://github.com/SunPodder/relay-pc

This client supports Windows, Linux, and macOS, and is designed to work seamlessly with this Android app.

Protocol

• All communication uses a 4-byte big-endian length-prefixed JSON envelope.
• See protocols/ for protocol details.

Contributing

Pull requests and issues are welcome!

License

MIT License