Summary

Sumire is a privacy-focused Japanese keyboard for Android, offering 100% offline functionality by processing all input and conversions on-device. It targets users prioritizing data security and those seeking a highly customizable typing experience, built upon the robust mozc engine.

How It Works

The keyboard leverages the open-source mozc engine, the core of Google's Japanese IME, for accurate, context-aware text conversion. Its primary design principle is absolute privacy, achieved by eliminating the need for an INTERNET permission and performing all operations locally. This approach is enhanced by advanced personalization features, including a powerful user dictionary, customizable snippets, and user-defined keyboard layouts, all developed using Kotlin and Jetpack libraries for a modern, efficient user interface.

Quick Start & Requirements

Installation is available via Google Play, F-Droid (Lite version), or the project's Releases page. After installation, enable Sumire in Android's Language & input settings and select it as the active keyboard. Building the project requires Android Studio, Gradle Plugin 8.10.1, JDK 17, Python 3, and CMake for optional Zenz model generation.

Highlighted Details

• 100% Offline & Secure: Operates without the INTERNET permission, ensuring data stays on the device. Learning data is encrypted with AES-256.
• Powerful User Dictionary & Snippets: Supports forward-matching predictions and full import/export capabilities for user-defined words and phrases.
• Ultimate Customization: Allows users to define custom key layouts, adjust key height and sensitivity, and tailor the typing experience.
• Modern Architecture: Developed in Kotlin with Jetpack libraries for a smooth, responsive UI, optimized for various Android devices including tablets.

Maintenance & Community

The project welcomes contributions via bug reports, feature requests, and pull requests, primarily managed through the GitHub Issues page. The copyright is held by Kazuma Naka (© 2025).

Licensing & Compatibility

Sumire is released under the permissive MIT License, making it suitable for commercial use and integration into closed-source applications.

Limitations & Caveats

Advanced features like AI-powered prediction (Zenz) and translation (Gemma) are available only in the fullStandard build variant; the F-Droid and liteStandard versions exclude these. Building the Zenz models requires local setup with Python and CMake, downloading large model files during the build process.