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Snapshot 0 · 2026-11-04T12:47:28Z · Rust · MIT
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c555544fe090e18decd43af91c1c8c4b5769656a5fd65bb0873951294e6059b0GitHub description at capture
Minecraft: Java Edition 26.3 rewritten from scratch in Rust, checked against vanilla with 281 differential harnesses. Get it with the Horizon launcher.
README at capture
<p align="center">
<img src="docs/media/banner.webp" alt="The Horizon website: the game you know, rebuilt in Rust" width="100%">
</p>
<p align="center">
<a href="https://github.com/horizon-rust/horizon/actions/workflows/ci.yml"><img src="https://github.com/horizon-rust/horizon/actions/workflows/ci.yml/badge.svg?branch=main" alt="CI"></a>
<img src="https://img.shields.io/badge/Minecraft-Java%2026.3-5D9C3F" alt="Minecraft Java 26.3">
<img src="https://img.shields.io/badge/Rust-stable-B7410E?logo=rust&logoColor=white" alt="Rust">
<img src="https://img.shields.io/badge/vanilla%20parity-100%25-F0795A" alt="Vanilla parity 100%">
<a href="#project-status"><img src="https://img.shields.io/badge/player--visible%20gaps-0%20open-F0795A" alt="Player-visible gaps open"></a>
<img src="https://img.shields.io/badge/platform-Linux%20%7C%20macOS%20%7C%20Windows-2A2470" alt="Linux, macOS and Windows">
<a href="LICENSE"><img src="https://img.shields.io/badge/license-MIT-3B2F7E" alt="MIT license"></a>
</p>
<p align="center">
<a href="https://playhorizon.dev"><b>Website</b></a> ·
<a href="#download"><b>Download</b></a> ·
<a href="https://playhorizon.dev/docs/"><b>Documentation</b></a> ·
<a href="https://github.com/horizon-rust/horizon/releases"><b>Release notes</b></a> ·
<a href="ROADMAP.md"><b>Roadmap</b></a> ·
<a href="#project-status"><b>Project status</b></a> ·
<a href="#contributing"><b>Contributing</b></a>
</p>
# Horizon
Minecraft: Java Edition 26.3, rewritten in Rust. Same worlds, same rules, same terrain, checked against the Java game by more than 300 differential harnesses. Free, open source and unofficial.
> Not an official Minecraft product, nor approved by or associated with Mojang or Microsoft. Horizon contains no Minecraft code, assets or data: you need your own copy of Java Edition 26.3.
## Download
Get **the Horizon launcher** from [playhorizon.dev](https://playhorizon.dev) or [the launcher releases](https://github.com/horizon-rust/horizon/releases?q=launcher-v&expanded=true) (Linux x86-64, macOS on Apple Silicon, macOS on Intel from the next Nightly, Windows x64). It installs and updates the game, prepares its files from your copy of Minecraft, and updates itself.
**You need** a Microsoft account that owns Java Edition ([why](docs/microsoft-account.md)) and a GPU with Vulkan or OpenGL 3.3 (Linux), Vulkan or DirectX 12 (Windows), or a Mac (Apple Silicon, or Intel from the next Nightly). An existing Minecraft install (official launcher, Prism, MultiMC...) is reused; without one, Play downloads 26.3 from Mojang for your account. Step by step: [Install and first launch](https://playhorizon.dev/docs/install).
<table>
<tr>
<td width="50%"><img src="docs/media/launcher-play.webp" alt="The launcher's Home page: the selected instance ready to play, the version picker, Join a friend and the instance's tabs"></td>
<td width="50%"><img src="docs/media/launcher-settings.webp" alt="The launcher's Settings page: Microsoft account, offline name, updates, appearance and accent colour"></td>
</tr>
</table>
## What works today
- **The game:** vanilla world generation, mobs, villagers, raids, redstone, every command, the HUD and the recipe book, on vanilla saves. Worlds from 1.8 to 26.2 are upgraded. [Status](#project-status).
- **Extras:** new menus, graphics presets, distant terrain up to 1024 chunks, controllers, zoom, minimap and more, off by default where they change the vanilla look. [Settings](https://playhorizon.dev/docs/settings).
- **Packs:** resource packs, and data packs with functions, predicates, item modifiers and world generation.
- **Multiplayer:** invite friends with a code, Open to LAN, join servers (online mode included). [Multiplayer](https://playhorizon.dev/docs/multiplayer).
- **Mods:** content mods (blocks, items, data) and native Rust mods, built by the launcher with nothing to install. Java mod jars do not run. [Mods](https://playhorizon.dev/docs/mods).
In the Rust client, with vanilla assets and no mods or shaders:
<table>
<tr>
<td colspan="2"><img src="docs/media/sunset.webp" alt="Sunset over a savanna river valley and a plains village"></td>
</tr>
<tr>
<td width="50%"><img src="docs/media/survival.webp" alt="Survival at dusk: a zombie walks up, with the hotbar, health, hunger and experience"></td>
<td width="50%"><img src="docs/media/settings.webp" alt="Vanilla's Video Settings screen with Horizon's own buttons at the top: Horizon Graphics and Advanced Graphics"></td>
</tr>
<tr>
<td width="50%"><img src="docs/media/village.webp" alt="A plains village among savanna hills, with farms, villagers and an iron golem"></td>
<td width="50%"><img src="docs/media/nether.webp" alt="A crimson forest in the Nether with a zombified piglin"></td>
</tr>
</table>
## Host a server
The launcher's **Servers** page creates, starts, backs up and updates a server, and invites friends over Tailscale. On a VPS, `horizon-server` installs with one command and needs no Java. [Host a server](https://playhorizon.dev/docs/hosting) ([reference](docs/hosting.md)).
## Modpacks
The launcher imports Modrinth and CurseForge packs and plays the mods Horizon can carry over: today, content mods made of data and assets, not Java code. [Modpacks](https://playhorizon.dev/docs/modpacks).
## Agent control
AI agents and scripts can play Horizon. `horizon-ctl`, shipped with the game, reads its state as JSON and acts like a player; `horizon-ctl mcp` serves the same commands over MCP.
```sh
horizon-ctl launch --world Survival --seed 5 --wait # finds the version the launcher installed
horizon-ctl state # position, health, food, target, screen...
horizon-ctl find-block birch_log # the nearest logs
horizon-ctl goto -0.5 65 -2.5 --near 2.5 # walks there along a path
horizon-ctl break -1 65 -3 # mines it; replies with the drops
horizon-ctl open-inventory && horizon-ctl click-slot 0 # menus: slots, buttons by label, text fields
```
Commands block until done and reply with the result; `horizon-ctl help` lists them all. [Agent control](docs/native-client.md#agent-control-horizon-ctl-and-mcp).
## Build from source
Needs Rust 1.90+, Python 3.10+, JDK 25, and on Linux `libasound2-dev libudev-dev`. `horizon-prepare` builds the game's resources from **your own copy** of Java Edition 26.3 (checked against `research-lock.json`) and never downloads it:
1. **Client:** play 26.3 once in the official launcher. Horizon reads `~/.minecraft` (or `--minecraft-dir` / `HORIZON_MINECRAFT_DIR`).
2. **Server jar:** the 26.3 server jar (`downloads.server.url` in `versions/26.3/26.3.json`), passed once with `--server-jar` or `HORIZON_SERVER_JAR`.
```sh
git clone https://github.com/horizon-rust/horizon.git
cd horizon
cargo run --release -p horizon-prepare -- --prepare --server-jar ~/Downloads/server.jar # needs JDK 25
cargo run --release -p horizon-prepare -- sounds # optional: sounds from your launcher install
cargo run --release -p horizon-client
```
Prepared files land in the gitignored `.local/`: never commit or share them. Options, controls and architecture: [the native client guide](docs/native-client.md); all developer docs: [docs/README.md](docs/README.md).
## Roadmap
What is in progress, what comes next and where to help: [ROADMAP.md](ROADMAP.md), or [playhorizon.dev/hub](https://playhorizon.dev/hub) with the work board and what shipped.
## Contributing
Issues and pull requests are welcome: read [CONTRIBUTING.md](CONTRIBUTING.md) (vanilla first, small pull requests). Questions: [Discord](https://discord.gg/playhorizon). Before a pull request, run the self-check and paste its output:
```sh
git config core.hooksPath .githooks
python3 tools/pr_ready.py
```
It runs rustfmt, clippy, the touched crates' tests, the Python tests, the public-tree check and the vanilla harnesses your change affects. Never commit game files, decompiled source or prepared resources.
## Project status
**Player-visible gaps: 0 open** of the 833 the [port ledger](tools/port_ledger.py) found, reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that Horizon doesn't have yet. By area: Animals [0](https://github.com/horizon-rust/horizon/issues/3512); Monsters and bosses [0](https://github.com/horizon-rust/horizon/issues/3513); Entities, projectiles, vehicles and decorations [0](https://github.com/horizon-rust/horizon/issues/3514); Items, enchantments and inventories [0](https://github.com/horizon-rust/horizon/issues/3515); Blocks, redstone and fluids [0](https://github.com/horizon-rust/horizon/issues/3516); World, world generation and saves [0](https://github.com/horizon-rust/horizon/issues/3517); Screens, HUD and client packets [0](https://github.com/horizon-rust/horizon/issues/3518); Entity and block rendering, models [0](https://github.com/horizon-rust/horizon/issues/3519); Server and players on the server [0](https://github.com/horizon-rust/horizon/issues/3520); Mob AI, villagers and raids [0](https://github.com/horizon-rust/horizon/issues/3521). This number goes down as gaps close (`tools/parity_gaps.py`); the harness results below say that what is tested matches.
The table is the project's own audit: every subsystem matches vanilla in every harness that compares it. 100% means 100% of what the harnesses compare, not that nothing else differs.
### Java parity: 100%
Scores: 0 (absent), 0.25 (started), 0.5 (playable, major features missing), 0.75 (mostly complete) or 1 (complete and verified by differential tests); the percentage is their average. Last audited 2026-10-13: the harnesses pass on Linux and macOS. The [port ledger](tools/port_ledger.py) adds a method-by-method view of what is ported.
| Subsystem | Score | Main gaps |
| --- | ---: | --- |
| Window, input and game loop | 1 | None: game loop, options, camera, auto-jump, toggle sprint/sneak and frame limiter match |
| Assets and resources | 1 | None: item models match over 196,290 stacks; the resource pack screen over 3,000 sessions |
| Network protocol and multiplayer | 1 | None: joins vanilla servers; the dedicated server matches vanilla's files, login, configuration, play and command tree; LAN discovery over 462 cases (offline mode only) |
| Chunk storage and palettes | 1 | None: client and saves share paletted containers, identical to vanilla over 266 scenarios |
| Section meshing | 1 | None: 112 scenes and over a million quads identical to vanilla |
| Rendering | 1 | None: entity models, block entity renderers (407 cases) and animations (296), HUD overlays (2,200 states), the recipe book (600), player list, subtitles and world border match |
| Lighting | 1 | None: saved and relit light matches vanilla, slabs and stairs included |
| World generation | 1 | None: 2,352 whole chunks over 225 structure sites, in all three dimensions, identical to vanilla |
| Region files and saves | 1 | None: saves round-trip with vanilla; worlds from 1.8 to 26.2 upgrade as vanilla's DataFixers do |
| Entities and physics | 1 | None: attributes, spawn rules, natural spawning (15,500 cases), raids and patrols (1,900), `finalizeSpawn` (24,000) and mob AI (92 scenarios) match |
| Interaction and inventory | 1 | None: menu clicks over 8,000 sequences; recipe book placement (6,000), buttons (1,200), saved book (1,500), loom and crafter screens (1,600) |
| Menus, HUD and chat | 1 | None: every command (758 over 39,685 inputs), scoreboards (81,000 operations), the player list (872,000 draw calls), chat and its suggestions (3,000 sessions) match |
| Audio | 1 | None: the sound engine, sound events, music, situational music, ambience and subtitles match vanilla |
| Block behaviours and ticking | 1 | None: block updates, random ticks, redstone, dispensers (6,000 cases), crafters (4,000), container spills (4,000), copper golems and the sculk family (435 scenarios) match |
### Known issues
Skins served over https show the default skin unless already cached; pack icons show the unknown-pack texture in game; item tooltips lack attribute lines.
## Licence
[MIT](LICENSE), for the project's original work; dependencies keep their own licences ([notices](THIRD_PARTY_NOTICES.md)). Minecraft is a trademark of Mojang Synergies AB; its code and assets belong to Mojang and Microsoft under the [Minecraft EULA](https://www.minecraft.net/en-us/eula).
## Author
Made by [Ludovic Marie](https://lu4ovic.com) ([@ludovic111](https://github.com/ludovic111)).