Easy Data Fix
by VoxelBill
Easy Data Fix is a server-side library for mod authors who need to register custom data fixers, so that saved game data converts safely between versions.
What it does
The library wraps the DataFixerUpper classes that Mojang ships with the game, which are designed for incremental building of data transformations. Easy Data Fix gives modders a simpler route to register their own fixers without writing the full setup by hand, and it supports merging optimized data transformations so that several fixes can run together.
Only the server needs the mod, since it works on saved world data and does not change anything a player sees. It is published for Fabric and NeoForge across 17 release versions, 1.21 – 26.3, and the latest builds for 26.3 are dated 2026-07-20. The code is open source under the MIT License. Two catalog mods, 26.1 Backport and Woalk Datafixer, require it.
Key features
Custom data fixers
Mod authors can register their own data fixers so that custom saved data is converted between game versions.
Wrapped DataFixerUpper
The library builds on the DataFixerUpper classes from the game, adding a simpler interface to the existing utilities.
Merged transformations
Several data transformations can be merged and optimized, so a world upgrade runs fewer separate passes.
Local development setup
A source copy can be cloned and built locally, with a Java Development Kit of version 25 or higher required for the build.
Compatibility
Latest build for each game version and loader.
26.x5 of 5 versions with builds
1.21.x12 of 12 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Required by 2 mods
Use cases
Backporting mods
Projects such as 26.1 Backport rely on the library to convert data between game versions.
Datafixer work
Woalk Datafixer uses it as its base, so authors building on that mod share the same registration approach.
Who it’s for: Mod developers who write data-conversion code for custom blocks, items or world data. Players and most server owners do not need to work with it directly, since it is only installed as a dependency of the mods that use it.
How it compares
Monument Data Fix is a server-side data fixing mod under the MIT License, published for Fabric and NeoForge across 1.21 – 1.21.5. Data Tables is a Fabric mod under the MIT License for 1.21.7 – 1.21.8 that requires the server while the client stays optional. Unified API is open source under the GNU Lesser General Public License v3.0 only, runs on Fabric and NeoForge for 1.21.11 – 26.3, and can be installed on either side.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Easy Data Fix | Fabric and NeoForge | 1.21 – 26.3 | Server-side only | 2026-07-20 |
| Monument Data Fix | Fabric and NeoForge | 1.21 – 1.21.5 | Server-side only | 2025-06-12 |
| Data Tables | Fabric | 1.21.7 – 1.21.8 | Server required, client optional | 2025-08-07 |
| Unified API | Fabric and NeoForge | 1.21.11 – 26.3 | Client or server, optional | 2026-10-15 |
Questions
Does Easy Data Fix need to be installed on the client?
Which loaders does Easy Data Fix support?
Which Java version is needed to build the source?
In the catalog
Easy Data Fix is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 8,071 mods support Minecraft 26.3.
More from VoxelBill
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What the author says
A library that enables modders to register custom data fixers. Easy Data Fix is a small library mod that aids in creation of data fixers for mods, allowing custom mod game data to be converted between different versions of the game safly. The mod wraps the builtin DataFixerUpper classes which are as Mojang says "a…
Official listing
- Modrinth page
- modrinth.com/mod/easy-data-fix
- Owner
- VoxelBill
- Published
- 2026-04-11
- Updated on Modrinth
- 2026-07-20
- Facts verified
- 2026-10-15