How to Install Sandustry Mods With Fluxloader

What Fluxloader is

Fluxloader is the community mod loader for Sandustry — the project previously known as modloader. It lets you enable gameplay mods, quality-of-life tweaks and companion tools without recompiling the game.

It is a Node.js application, with an updater script for Windows (.bat) and for Unix-like systems (.sh).

Setup, in the order it happens

1. Get the loader. Releases are published on the project’s GitHub repository.
2. Let it generate its config. On first run it creates a fluxloader-config.json and a dedicated mods folder.
3. Point it at the game if asked. Auto-detection handles most installs; if it fails, you supply the path to the game executable yourself.
4. Drop mods into the mods folder.

If you want to run the loader from source instead, the repository documents cloning it, installing dependencies, and starting it with npm start.

npm install && npm start

Custom maps

The Sandustry Custom Map Loader is a separate mod that runs on top of Fluxloader. It handles creating and selecting custom maps, so you do not need a separate install path for map content.

What the modding API actually exposes

Worth knowing before you plan a mod, because it shapes what is realistic.

Mods apply changes by patching files, through three documented functions:

Function	Purpose
addPatch(file, patchObj)	Standard file modification
addMappedPatch(fileMap, mapFn)	File mapping with a transform function
setPatch(file, tag, patchObj)	Tagged patches, for organisation

The documented patch style is string replacement against game files. Beyond patching, the API covers cross-environment communication (Electron, game and worker contexts), lifecycle event listeners such as scene loading, and configuration schema management.

What it does not document is a query API for game data — there is no documented interface for reading materials, recipes or building statistics. The modding guide is explicit about its own limits, advising that the source code is the final authority over the guide.

That matters for anyone hoping to build data tools on top of the loader: as documented, you are patching files, not reading a content database.

A caution about versions

Everything above describes the loader as it stood against the demo. Early Access ships with official modding tools of its own, and a loader built for the demo build will not necessarily survive that. Check the project’s own releases before assuming a mod still applies.