DropOut

A deterministic Minecraft launcher for reproducible, inspectable game environments.

English | Chinese

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What Is This

DropOut is a modern, developer-grade Minecraft launcher built around one idea: a game setup should be traceable like a software project.

Most launchers focus on starting the game. DropOut also keeps the surrounding environment understandable: account state, Java runtime, game version, loader, instance directory, assets, libraries, and launch logs.

Minecraft environments are complex systems. DropOut treats them as versioned workspaces.

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Project Shape

DropOut is a desktop application with three active surfaces:

Surface	Path	Stack	Purpose
Desktop shell	src-tauri/	Rust, Tauri 2	Authentication, downloads, Java/version resolution, instance storage, launch orchestration
Launcher UI	packages/ui/	React 19, shadcn/ui, Vite/Rolldown, Tailwind CSS 4	Main application interface rendered inside the Tauri webview
Documentation	packages/docs/	Fumadocs, React 19, React Router 7	Bilingual product and developer documentation

The Rust core owns side effects. The React UI invokes Tauri commands and renders state. The docs package explains the product, architecture, and user workflows.

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Features

• Microsoft authentication - device-code OAuth flow, Minecraft Services login, token refresh, and persisted account state.
• Offline accounts - local accounts for testing or non-network play.
• Instance system - isolated game directories with per-instance notes, memory overrides, Java arguments, version, and loader state.
• Minecraft version management - install, verify, list, delete, and launch local versions.
• Fabric and Forge support - loader version discovery plus installer flows for modded instances.
• Java management - local Java detection, compatibility checks, Adoptium catalog lookup, downloads, resume, and cancellation.
• Concurrent downloads - asset/library queues with progress events and recovery paths.
• Configuration editor - inspect and edit raw JSON/TOML launcher configuration.
• Release feed - GitHub release notes surfaced on the home screen.
• Game assistant - optional local or OpenAI-compatible helper for logs, crashes, and configuration questions.

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Quick Start

Prerequisites

• Rust toolchain from rustup.rs
• Node.js 22+
• pnpm 10+
• OS dependencies from the Tauri v2 prerequisites

Install Dependencies

This repository does not use pnpm-workspace.yaml. Install each JavaScript surface against the root lockfile:

pnpm install
pnpm -C packages/ui --lockfile-dir "$PWD" install
pnpm -C packages/docs --lockfile-dir "$PWD" install

pnpm install also runs the repository prepare script, which installs the local prek hooks.

Run The Desktop App

pnpm exec tauri dev

Tauri starts the React UI dev server through src-tauri/tauri.conf.json and opens the desktop window at http://localhost:1420.

Build A Desktop Release

pnpm exec tauri build

Release artifacts are produced by Tauri under the Rust target directory and configured bundle directories.

Run Package Surfaces Directly

pnpm -C packages/ui dev
pnpm -C packages/docs dev

The UI can run in a browser for layout work, but Tauri-backed flows require the desktop shell.

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Common Commands

Task	Command
Install root tooling	pnpm install
Install UI dependencies	pnpm -C packages/ui --lockfile-dir "$PWD" install
Install docs dependencies	pnpm -C packages/docs --lockfile-dir "$PWD" install
Run desktop app	pnpm exec tauri dev
Build desktop app	pnpm exec tauri build
Run UI dev server	pnpm -C packages/ui dev
Build UI bundle	pnpm -C packages/ui build
Lint UI	pnpm -C packages/ui lint
Run docs site	pnpm -C packages/docs dev
Build docs site	pnpm -C packages/docs build
Check docs types/content	pnpm -C packages/docs types:check
Test Rust workspace	cargo test --workspace

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Repository Layout

.
|-- assets/                 # README and project media
|-- crates/                 # Rust support crates and macros
|-- packages/
|   |-- docs/               # Fumadocs + React Router documentation site
|   `-- ui/                 # React launcher frontend
|-- scripts/                # Release and maintenance scripts
|-- src-tauri/              # Rust desktop backend and Tauri configuration
|-- Cargo.toml              # Rust workspace
|-- package.json            # Root tooling
`-- pnpm-lock.yaml          # Shared pnpm lockfile

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Architecture Notes

The command boundary is registered in src-tauri/src/main.rs. Feature modules live under src-tauri/src/core/:

• auth.rs and account_storage.rs handle Microsoft and offline account state.
• instance.rs owns isolated instance directories and metadata.
• game_version.rs, manifest.rs, and migration.rs resolve Minecraft versions and launch rules.
• fabric.rs, forge.rs, maven.rs, and downloader.rs install loaders, libraries, assets, and version files.
• java/ detects, validates, and persists compatible Java runtimes.
• modpack/, mods.rs, and content_search.rs handle modpack parsing, mod metadata, and content discovery.
• assistant.rs powers the optional troubleshooting assistant.

The UI keeps long-lived state in packages/ui/src/models/, renders routes from packages/ui/src/pages/, and shares reusable controls from packages/ui/src/components/.

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Roadmap

• Account persistence and token refresh
• Microsoft device-code login and offline login
• Java auto-detection and Adoptium download flow
• Fabric and Forge install paths
• Isolated instance/profile system
• GitHub releases integration
• Optional game assistant
• Multi-account switching
• Built-in mods manager
• Custom game directory selection
• Launcher auto-updater
• Import from PCL, HMCL, MultiMC, Prism Launcher, and other profiles

The public roadmap is tracked at https://roadmap.sh/r/minecraft-launcher-dev.

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Contributing

DropOut is built for long-term maintainability. Useful contributions usually improve one of these areas:

• instance and profile workflows
• mod loader compatibility
• Java/runtime detection
• downloader reliability
• UI/UX clarity
• documentation and troubleshooting coverage

Use the standard GitHub flow: fork, branch, commit, and open a pull request against HydroRoll-Team/DropOut.

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License

Distributed under the GNU Affero General Public License v3.0. See LICENSE for details.