UltraLib
by Sygikal
With UltraLib, data-driven Fabric mods get a small set of Java helpers for loading JSON, registering features and sorting lists.
What it does
UltraLib is a non-intrusive Java code library: it uses no mixins, so it adds no injections into vanilla code and relies on plain collection and utility classes. Its main purpose is to ease data-driven development and feature registration. Loading JSON data can be done through several methods, including a simple loader, a runnable loader and a detached runnable loader, and optional data can be parsed from JSON.
A registry function lets one object be turned into another object by a specified id. Sorting by list weight and an extremely light configuration round out the toolkit, and the library repackages Apache Commons classes, because the Apache copies included by default are not used directly. Some utilities are provided to keep common code short.
UltraLib runs on client and server, so both the server and every player need it. It is published for Fabric only, across 9 release versions 1.20 – 1.21.10, and its latest file, 1.0.7+1.20.1 for 1.20.1, was released on 2025-11-22. The project is licensed under All rights reserved, so it is not open source, though its source code is public.
Key features
Non-intrusive design
The library uses no mixins, so it can sit alongside other mods without altering how vanilla classes behave.
JSON data loading
Several loader classes read JSON data, and optional fields can be parsed without causing errors when absent.
Registry transformation
A registry function converts one object into another, selected by a specified id.
Sorting and utilities
List sorting by weight and small helper methods reduce repeated code in mods that use the library.
Compatibility
Latest build for each game version and loader.
1.21.x2 of 2 versions with builds
1.20.x7 of 7 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Required by 4 mods
Use cases
Who it’s for: The library suits mod developers who want shared Java helpers for data-driven features, and players who use the mods listed as requiring it.
How it compares
Simple Creator is a Fabric client and server mod under the MIT License, open source, for 1.20.1 – 1.21.4. env.json is a Fabric and Quilt mod with a custom license, not open source, that works on the client or the server, optional, for 1.20.1 – 1.21.1. Munchables is an open source Fabric client and server mod under the MIT License for 1.20.1 – 1.20.4, and it is a gameplay mod rather than a library.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| UltraLib | Fabric | 1.20 – 1.21.10 | Client and server | 2025-11-22 |
| Simple Creator | Fabric | 1.20.1 – 1.21.4 | Client and server | 2025-01-05 |
| env.json | Fabric and Quilt | 1.20.1 – 1.21.1 | Client or server, optional | 2024-09-09 |
| Munchables | Fabric | 1.20.1 – 1.20.4 | Client and server | 2024-03-15 |
Questions
Does UltraLib need to be installed on the server?
Which loaders does UltraLib support?
Which mods require UltraLib?
Can the source code be read?
In the catalog
UltraLib is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 15,569 mods support Minecraft 1.21.10.
More from Sygikal
Similar mods
What the author says
This is my penultimate library mod, meant for easing data-driven development and feature registration. It is non-intrusive (meaning no-mixins and such for broad compatibilty) and is purely a collection of helpful Java classes.
Official listing
- Modrinth page
- modrinth.com/mod/ultralib
- Owner
- Sygikal
- Published
- 2025-07-27
- Updated on Modrinth
- 2025-11-22
- Facts verified
- 2026-10-15