Appy

Turn any website into an APK, with a simple and easy-to-use UI.

Features

• On-Device APK Generation: Convert any website URL into a standalone Android APK directly on your device
• Customizable Apps: Set custom app name, package ID, and app icon for your generated APK
• Material 3 Expressive Design: Modern UI with glass-effect TopAppBar, emphasized transitions, and extra-large corner radii
• Binary Template Modification: Uses pre-compiled WebView template for fast APK generation without Gradle
• Automatic Signing: APKs are signed and ready for installation

Known issues

• Custom icons don't work
• Offline caching is experimental and may not work correctly on some advanced or dynamic websites

Technical Overview

Architecture

Appy uses a "Binary Template Modification" strategy to generate APKs without running a full Gradle build:

1. Template APK: A pre-compiled base-web-template.apk containing a WebView app is bundled in assets (built automatically from the template module)
2. ZIP Manipulation: Uses Zip4j to modify the template APK
3. Config Injection: Replaces assets/config.json with the user's URL and app configuration
4. Icon Injection: Replaces launcher icons at multiple densities with user-provided icon
5. APK Signing: Signs the modified APK using a bundled keystore

Project Structure

├── app/                                  # Main Appy application
│   ├── src/main/
│   │   ├── java/com/appy/
│   │   │   ├── MainActivity.kt           # Main entry point
│   │   │   ├── ui/
│   │   │   │   ├── theme/
│   │   │   │   │   └── AppyTheme.kt      # M3 Expressive theme
│   │   │   │   └── screens/
│   │   │   │       └── HomeScreen.kt     # Main UI with inputs
│   │   │   └── processor/
│   │   │       └── ApkProcessor.kt       # APK generation logic
│   │   ├── assets/
│   │   │   ├── debug.jks                 # Debug keystore for signing
│   │   │   └── base-web-template.apk     # WebView template (auto-generated)
│   │   └── AndroidManifest.xml
│   └── build.gradle.kts
│
├── template/                             # WebView template module
│   ├── src/main/
│   │   ├── java/com/webtemplate/
│   │   │   └── MainActivity.kt           # WebView activity
│   │   ├── assets/
│   │   │   └── config.json               # URL configuration placeholder
│   │   └── res/
│   └── build.gradle.kts
│
└── settings.gradle.kts

Building

Prerequisites

• Android Studio Arctic Fox or later
• JDK 17 or higher
• Android SDK with API 35

Build Commands

# Debug build (automatically builds template first)
./gradlew assembleDebug

# Release build (requires signing configuration)
./gradlew assembleRelease

The build system automatically:

1. Compiles the template module into base-web-template.apk
2. Copies it to app/src/main/assets/
3. Builds the main app with the template bundled

CI/CD

The project includes a GitHub Actions workflow (.github/workflows/appy_release.yml) that:

• Builds the release APK on push to version tags (e.g., v1.0.0)
• Signs the APK using GitHub Secrets
• Creates a GitHub Release with the APK

Required Secrets

• KEYSTORE_BASE64: Base64-encoded release keystore
• KEYSTORE_PASSWORD: Keystore password
• ALIAS: Key alias name

Permissions

The app requires the following permissions:

• READ_EXTERNAL_STORAGE / WRITE_EXTERNAL_STORAGE: For saving generated APKs (Android 10 and below)
• REQUEST_INSTALL_PACKAGES: For installing generated APKs

License

This project is open source. See LICENSE for details.