Solara

A minimal, privacy-first Android browser. Built with Kotlin and Jetpack Compose, powered by our own rendering and JavaScript engines.

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What it is

Solara is a browser for Android that does not rely on Chromium, WebView, or any third-party rendering engine. It uses Optima (our Rust rendering engine) to parse HTML and CSS, Solarium (our Zig Runtime engine) to run scripts, and Solarian (our Kotlin search API) for search.

The goal is a browser that is:

• Small. No 200 MB engine dependencies.
• Fast. Native rendering, no bridge overhead.
• Private. No telemetry, no accounts, no tracking.
• Beautiful. Material 3, glass-morphism, quiet design.

Solara is the flagship browser for the SolaraStudio ecosystem. For older devices, see Solaria.

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Architecture

Solara is a thin Android shell around two native engines.

Layer	Component	Language	Responsibility
1. UI	Solara UI	Kotlin · Compose	Screens, tabs, toolbar, theme, gesture handling
2. State	ViewModels	Kotlin · Coroutines	StateFlow, business logic, lifecycle
3. Data	Repositories	Kotlin	Room, DataStore, caching, preferences
4. Bridge	JNI Bridge	Kotlin ↔ C ABI	Native calls, callbacks, handle table
5. Engine —> Render	Optima	Rust	HTML parse · CSS cascade · DOM · layout · paint
6. Engine —> Runtime	Solarium	Zig	Runtime · event loop · DOM bindings
7. Service	Solarian	Kotlin	Search providers, suggestions
8. Surface	SurfaceView	Android	GPU-backed render target

• Optima — rendering engine. Rust.
• Solarium — runtime engine. Zig.
• Solarian — search provider API. Kotlin.

Solara itself does not implement HTML, CSS, or JavaScript. It provides the UI shell, state management, and native integration.

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Screenshots

To be added.

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Requirements

To build Solara you need:

• JDK - 17 or later
• Android SDK - with platform 36 and build-tools 36.0.0
• Android NDK - 25.1.8937393 (for building Optima and Solarium)
• Rust 1.85+ with the four Android targets
• Zig 0.14+ (for building Solarium)
• Gradle 9.5 (included via wrapper)

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Building

Clone

git clone https://github.com/SolaraStudio/Solara.git
cd Solara

Configure credentials

Solara depends on prebuilt Optima artifacts hosted on GitHub Packages. Add your credentials to ~/.gradle/gradle.properties:

GITHUB_ACTOR=your-github-username
GITHUB_TOKEN=ghp_your_personal_access_token

The token needs the read:packages scope.

Build the app

cd android
./gradlew assembleRelease

Output:

android/app/build/outputs/apk/release/app-release.apk

For a debug build:

./gradlew assembleDebug

Build with a specific ABI

./gradlew assembleRelease -Pabi=arm64-v8a

Supported ABIs: arm64-v8a, armeabi-v7a, x86, x86_64.

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Project structure

Solara/
├── android/                  Android application
│   ├── app/                  Application module
│   │   └── src/main/
│   │       ├── java/com/solara/browser/
│   │       │   ├── data/     Room, DataStore, repositories
│   │       │   ├── domain/   Models, use cases
│   │       │   ├── engine/   JNI bindings to Optima and Solarium
│   │       │   ├── ui/       Compose screens, components, theme
│   │       │   └── di/       Hilt modules
│   │       ├── res/          Resources
│   │       └── jniLibs/      Native libraries (populated at build time)
│   ├── build.gradle.kts
│   └── settings.gradle.kts
├── docs/                     Architecture and design notes
├── scripts/                  Build and maintenance scripts
└── README.md

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Configuration

Settings are exposed in the app itself. For development, the following environment variables are recognised during build:

Variable	Purpose
APP_VERSION	Override version name
OPTIMA_VERSION	Optima artifact version to depend on
VERSION_SUFFIX	Append a suffix to the version (e.g. -SNAPSHOT)

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Testing

cd android
./gradlew test
./gradlew connectedAndroidTest

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Contributing

Contributions are welcome. Before starting, please read CONTRIBUTING.md.

For larger changes, open an issue first so we can align on the approach before you write code.

The process:

1. Fork the repository.
2. Create a feature branch.
3. Make your changes, with tests where reasonable.
4. Run ./gradlew check locally.
5. Open a pull request.

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Related repositories

Repository	Purpose
Solaria	Android browser for older devices
Optima	Rendering - engine (Rust)
Solarium	Runtime - engine (Zig)
Solarian	Search provider API (Kotlin)
web	Website
docs	Documentation

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Acknowledgements

Solara stands on the work of others:

• Jetpack Compose — declarative UI toolkit
• Material 3 — design system
• Hilt — dependency injection
• Room — persistence

And the engines that make it a browser:

• Optima — rendering
• Solarium — runtime
• Solarian — search

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License

Solara is licensed under the Mozilla Public License 2.0. See LICENSE for the full text.