Zenith

A lightweight, native Minecraft launcher for macOS, written in Rust with GPUI (the GPU-accelerated UI framework behind Zed).

Status: early and actively built. Vanilla, Fabric, and Quilt launch today; Forge/NeoForge and Modrinth modpacks are on the roadmap.

Features

• Real version list from Mojang's manifest
• Downloads the game — client jar, libraries (with OS/arch rules), natives, and assets (parallelized)
• Launches java with the correct classpath/arguments for both modern and legacy version formats
• Mod loaders: Vanilla, Fabric, Quilt (via their meta APIs and inheritsFrom merging)
• Single instance with start/stop control and a live, copyable console of launcher + game output
• Microsoft sign-in (device-code OAuth → Xbox Live → XSTS → Minecraft) — fully implemented; needs an Azure app ID approved for the Minecraft API
• Minimal, Zed/Linear-flavored UI (IBM Plex Sans + IBM Plex Mono)

Requirements

• Rust nightly (pinned via rust-toolchain.toml — GPUI uses unstable features)
• A Java runtime on PATH (override with ZENITH_JAVA); modern versions need Java 21+
• macOS with the Metal toolchain (xcodebuild -downloadComponent MetalToolchain if the shader build fails)

Run

cargo run

Game data lives in ~/Library/Application Support/zenith-launcher/.

Microsoft sign-in (optional)

Minecraft auth requires your own Azure app registration (personal-accounts only, public-client flows enabled), and Microsoft must grant it Minecraft API access. Provide the client ID via:

ZENITH_CLIENT_ID=your-azure-client-id cargo run

Without it (or until approved), the launcher runs in offline mode.

Architecture

A Cargo workspace, GPUI isolated to the UI layer:

Crate	Responsibility
core	Domain types (Loader, Account, VersionEntry, Session) + log/progress bus. No IO, no GPUI.
net	Mojang manifest + Microsoft/Xbox/Minecraft authentication
store	On-disk paths and layout
launch	Resolve → download → classpath/natives → spawn/kill the game
ui	Theme/palette, layout helpers, shared widgets
app	The zenith-launcher binary: app state, views, wiring

core, net, store, and launch are plain Rust (testable without a window); only ui and app depend on GPUI.

License

MIT