Thread.JS

This is a mod that enables usage of the Javascript programming language and debugger for Fabric mods.

152 Downloads

fabriclibrary

Rent Server with this Mod

About this Mod

This is a mod that enables usage of the Javscript programming language and debugger tools for Fabric mods.

This is still being developed and tested. If you have any issues or are missing any features, please contact me on discord

For an example mod please checkout this github repo

Roadmap

Debugging directly in the code (VsCode or Intellij)
Support mixins
Custom registries (new blocks, items, entities, GUIs)
Client-side rendering
Networking — custom packets between client/server.

ThreadJS weaves JavaScript into Fabric.

Available Versions

Thread.JS 0.0.1release

MC 1.21.11fabric

February 20, 2026

How to Install Thread.JS on Your Server

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.11).

Install Mod

Open the mod browser in the dashboard and search for "Thread.JS". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

fabric

Minecraft Versions

1.21.11

Server-side

~ Optional

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Thread.JS server crashes on startup – what to do?

Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.11). You can switch loaders with one click in the panel.

Is Thread.JS compatible with fabric?

Thread.JS officially supports fabric for Minecraft 1.21.11. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Thread.JS – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Thread.JS consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.