Kiln

Alpha 0.1.0-alpha, tested on macOS (Apple Silicon)

Kiln

Java mods in Horizon

Kiln runs Java (Fabric) mods in Horizon, the Rust rewrite of Minecraft: Java Edition 26.3, the way Proton runs Windows games on Linux: the mod's code runs as it is, and its calls to Minecraft's classes and the Fabric API become calls into Horizon.

Download Install guide Source code

Latest public release 0.1.0-alpha; 0.1.1-alpha is coming. Not tried on Windows or Linux yet.

.jar

How it works

Kiln is a native Horizon mod. It starts Java beside the game, not inside it, runs each mod's entrypoints from its fabric.mod.json, gives mods the game's state every tick, and draws what they draw on the HUD.

  1. Install Kiln once

    The Horizon launcher builds Kiln into the game. You need the Horizon launcher with 26.3 prepared, and Java 25. The steps are in INSTALL.md in the repository, where they stay current.

  2. Drop in your mods

    Put .jar mods into <game folder>/kiln/mods/.

  3. Play

    Kiln runs each mod's entrypoints, gives it the game's state every tick, and draws what it draws on the HUD.

  1. Fabric mod a .jar, unchanged
  2. Kiln Java, beside the game
  3. Horizon Rust
The mod's code runs as it is. Its calls to Minecraft's classes and the Fabric API become calls into Horizon.

Kiln + Horizon's mod browser

Horizon brings the data, Kiln the code. Kiln and Horizon's mod browser work together, each taking one half of a Java mod.

One Java mod, one .jar, two halves

Data: Horizon

Horizon's launcher carries a Java mod's data into a Horizon content mod.

  • blocks
  • items
  • recipes
  • structures

Code: Kiln

Mods whose features need Java code are marked Partly in the mod browser. Kiln runs that code, beside the game.

  • entrypoints
  • game state every tick
  • HUD drawing

What runs today

Each row says what works, nothing more. The full list has every mod tried so far, with search and a filter by status.

Mod Version What works
Kiln Speedrun Timer WorksThe Kiln project's own Fabric mod 0.1.0-alpha Automatic splits: Nether, Bastion, Fortress, Blind, Stronghold, End, Finish. RTA and IGT. Personal best with deltas.
Show FPS WorksFrom Modrinth, unchanged 2.0.0 Its FPS counter.
Illager Warship Works 1.0.0 Its warship generates in new worlds.

All supported mods

What's new

The latest releases, in short. The full history is in CHANGELOG.md; the files are on Releases.

  1. 0.1.0-alpha

    First alpha: Kiln 0.1.0 and Kiln Speedrun Timer 0.1.0-alpha. Tested on macOS (Apple Silicon) with Horizon Nightly 2026-10-29; the timer also in Minecraft 26.3 with Fabric.

    • Kiln 0.1.0 runs Fabric client mods in Horizon: Java in a process of its own, a client tick 20 times a second with the game's state, keys and advancements, and the mods' HUD drawn in the game.
    • Kiln Speedrun Timer 0.1.0-alpha, a Fabric mod for Minecraft 26.3: Any% with automatic splits, RTA and IGT, personal best and best splits with deltas, keys J, K and U.
    • Spike: a JVM inside a Rust program through hand-written JNI, and the spike's Fabric mod.
    • Project documents: DECISIONS.md, PROTON.md, README (en, ru).

    Release notes

Roadmap

The goal is Tech Reborn, an industrial mod, running unchanged. The steps on the way are below; the details are in ROADMAP.md. No dates are promised.

  1. 0.1 now

    Alpha

    0.1.0-alpha is out; 0.1.1-alpha is coming. Entrypoints, the game's state every tick, the HUD.

  2. 0.2

    Measure it

    Minecraft's libraries for mods, and a testbench of 139 probes.

  3. 0.3

    Code next to data

    Mods' code next to Horizon's import of their data.

  4. 0.4

    Machines

    Block entities, menus, energy.

  5. 0.5

    Mixin

    Support for Mixin.

  6. 1.0

    Tech Reborn

    An industrial mod, running unchanged.

FAQ

The short answers. The code and INSTALL.md in the repository have the long ones.

Is it safe?

Native Horizon mods run without a sandbox, with your rights, and Kiln is one of them. The launcher builds it only after you explicitly agree. Kiln is open source: read the code first. The Java mods it runs also run with your rights, as any Java mod does.

Which mods work?

Fabric mods for 26.3 that use what Kiln already covers. The list of mods grows with each release and says how far each one has been checked. There is no Mixin support yet; it is on the roadmap for 0.5.

Does it run on Windows or Linux?

Not tested yet. So far Kiln has been tried on macOS with Apple Silicon only.

Is it official?

No. Kiln is not affiliated with Horizon, Mojang or Microsoft. It is an independent open-source project.