Cubby

The lightweight Minecraft launcher.

Cubby keeps each of your worlds in its own instance, with its own version, loader, mods and settings. You pick one and press Play: Cubby downloads the game, the loader and the right Java, then gets out of the way.

It's a native app built with Rust and Tauri, so there's no bundled browser and no Java just to open the launcher. The installer is about 11 MB.

What it does

• Instances. Any release, snapshot or old version, with Fabric, Quilt, Forge or NeoForge. Give each one an emblem and a colour so you can spot it at a glance.
• Mods, resource packs and shaders from Modrinth and CurseForge, searched from inside the launcher. Cubby only shows what works with the instance you're installing into, adds the dependencies, and finds updates for what you already have.
• Modpacks from Modrinth, CurseForge, FTB, ATLauncher and Technic, or from a .mrpack or .zip you downloaded.
• Crash diagnosis. When the game crashes, Cubby reads the log, tells you what most likely went wrong and offers a fix, like turning off a mod made for another version of the game.
• While you play: the live game log, your screenshots as you take them, and the status of the server you joined.
• Also: world backups, import from Prism Launcher, several accounts, and night, day and high-contrast themes.

Find mods	Mod pages	When it crashes

Download

Cubby runs on Windows 10 and 11, on macOS 11 or later (Apple Silicon and Intel) and on 64-bit Linux. Get it from the releases page.

The full game needs a signed-in Microsoft account that owns Minecraft: Java Edition. Without one, Cubby only starts the Minecraft demo.

Versions

Cubby uses calendar versions: 2026.11.0 is the first release of November 2026, 2026.11.1 the next one that month. Test builds add -alpha.N or -beta.N. The full year keeps them apart from Minecraft's own version numbers.

To publish a release, push a tag such as v2026.11.0: GitHub Actions builds the installer and attaches it to a draft release.

Building from source

You need Rust 1.90 or newer and Node.js 20 or newer. On Windows, the WebView2 runtime (already there on Windows 11). On Linux, WebKitGTK 4.1 and its development files (libwebkit2gtk-4.1-dev on Debian and Ubuntu).

git clone https://github.com/benjaminbrtrd/Cubby cubby
cd cubby/ui
npm install
cd ..
npm run tauri dev

npm run tauri build makes the installer in target/release/bundle/.

Two values can be set at build time:

• CUBBY_CURSEFORGE_API_KEY: a CurseForge API key. Without it, CurseForge search is turned off, and everything else works.
• CUBBY_MSA_CLIENT_ID: optional. Cubby already has its own Azure application id, approved by Mojang; set this only to sign in through another one.

The interface also runs in a plain browser with sample data, which is handy for working on screens: npm run dev in ui/.

How the code is laid out

crates/
  cubby-common      shared types, paths, HTTP client
  cubby-meta        Mojang versions, Fabric, Quilt, Forge and NeoForge installs
  cubby-java        finding, picking and downloading Java
  cubby-auth        Microsoft sign-in
  cubby-instance    instances, their content, backups, settings
  cubby-launch      building the command line and running the game
  cubby-modrinth    Modrinth search, installs and updates
  cubby-curseforge  CurseForge
  cubby-ftb         Feed The Beast
  cubby-atlauncher  ATLauncher
  cubby-technic     Technic
  cubby-packinstall installing a modpack plan
src-tauri/          the desktop app: window, commands, events
ui/                 the interface, in Svelte

Each crate builds and tests on its own. cargo test --workspace runs the offline tests; the ones that call real services are marked #[ignore] and run with cargo test -- --ignored.

Contributing

Bug reports and pull requests are welcome. See CONTRIBUTING.md.

License

Cubby is free software under the GNU General Public License v3.0.

Not an official Minecraft product. Not approved by or associated with Mojang or Microsoft. Made by Benjamin · contact@cubbylauncher.com