Komai (こまい)

A fine Matrix chat app you can get to love

🦁 Komai is a desktop-first Matrix chat application built with Rust, C++ and QML. It traces its origins to a usability-focused fork of nheko, rebuilt around the Rust matrix-sdk runtime with a growing Rust core.

🤖 Komai is built with AI. Professional engineers + AI coding agents (Claude Code, Codex) working together to build a complex native application in a language stack that isn't the team's primary expertise. We think AI in capable hands can deliver above-average results.

Komai was created by the etke.cc team, but contributions by anyone are welcome! It's fully Free Software (GPL-3.0-or-later), with no CLA and no contributor gatekeeping.

If you're curious about the origin of this project and its name, see the 🦁 Identity documentation page.

🎯 Design Philosophy

• Desktop-first UX — optimized for large screens
• Readable and easy to use — comfortably readable text, great color contrast, large hit targets, and interaction patterns that respect Fitts's law
• Yours to shape — themeable, customizable, and config-management friendly via plain-YAML files
• Responsive by design — native performance is a design constraint
• Educate, don't over-abstract away — like Arch Linux, we prefer exposing Matrix's real concepts over hiding them
• For both grandma and power users — neither dumbed down nor buried in complexity

🌟 Features

• Matrix messaging with end-to-end encryption support (powered by the Rust matrix-sdk runtime)
• Attachments (file, image, audio) with a built-in media viewer featuring gallery navigation and in-app video playback
• Voice transcription -- long-press Space to record speech and have it transcribed into the composer; works with OpenAI cloud or any OpenAI-compatible local server
• Calls -- legacy 1:1 voice works; video and screen-share have known send-side bugs; no Element Call support yet. Disabled by default
• Emoji messages (with custom emojis). Support for richer emoji discovery via localized Unicode CLDR keywords (for example, :whiskey finds 🥃)
• Replies, Discord-style threads, and message forwarding
• Multi-account support via dedicated application profiles
• 10+ built-in themes, maintained to meet WCAG AA contrast for common UI text pairings. Also 🗂️ user-themable
• 30+ languages with inherited nheko translations and AI-assisted gap filling
• Lots of configuration settings, grouped into tabs and searchable
• Polished Room Directory with first-class Matrix Rooms Search support (enabled by default via matrixrooms.info by etke.cc), language filtering, and room size filtering
• Good support for hundreds of rooms and spaces
• Browser-style room tabs for juggling multiple conversations at once, with pinning and more (a power-user feature still rare among Matrix clients)
• Keyboard-driven main chat workflow, with human and Vim-style shortcuts
• Selection mode for bulk actions (forwarding, moderation)
• Quick & relatively lightweight native application (Rust, C++ and QML). No Electron here
• Human- and agent-ready local automation via Model Context Protocol (MCP), CLI commands, and the D-Bus API
• Fully Free Software (GPL-3.0-or-later), with no CLA and no contributor gatekeeping

Curious where Komai came from and what changed along the way? See 📄 Differences from nheko.

📸 Screenshots

Welcome	Sign in	Register
Main view	Settings	Dark Matrix theme

More screenshots are inlined on individual feature pages — see the 👤 User Guide.

📥 Installation

Linux (x86_64): Komai ships as AppImage, Flatpak, and Snap packages on the GitHub Releases page, plus a komai package on the Arch Linux AUR.

Windows (x64): a portable ZIP for Windows 10 (22H2+) and later is attached to each GitHub release. The build excludes VOIP (no voice or video calls) and isn't code-signed, so the first launch shows a SmartScreen warning that needs More info -> Run anyway.

macOS: there are no official builds. macOS hasn't been tested by the maintainers; tentative pointers for building from source are in 📄 Native build on macOS.

See 📄 Installation for download links and install commands. To build Komai yourself, see 📄 Native build.

📚 Documentation

See 📄 Documentation for the full list of guides, including settings, theming, translations, and packaging.

🤝 Contributing

• Development — building, testing, and code contributions
• Translations — improving translations or fixing awkward wording

🆘 Support

• Matrix room: #komai:etke.cc
• GitHub issues: etkecc/komai/issues

🙏 Acknowledgements

Komai started as a fork of nheko by the Nheko-Reborn team. We're grateful for the original application and the Qt/QML groundwork that made Komai possible.

Komai's Matrix protocol and end-to-end encryption core is built on the matrix-rust-sdk by the matrix.org team — a polished, well-documented Rust runtime that made the move off mtxclient + libolm tractable for us, and that positions Komai for everything that comes next in the Matrix ecosystem.

• Boring Avatars — default avatar generation algorithms (Beam, Marble, Bauhaus styles), ported from TypeScript to C++
• Fluent UI System Icons — primary icon set (MIT)
• Font Awesome Free — supplementary icons and brand logos (CC BY 4.0)
• Tinted Theming (Base16)