JsonEM
JsonEM is a Fabric and Quilt library that defines entity models as JSON, so modders and pack makers can edit them without writing Java code.
What it does
Entity models are described in JSON files that follow the resource pack format. The library reads those files at runtime and applies them to the entities they name, which lets a model be changed by editing text instead of recompiling a mod. Resource pack makers and modpack makers can add or adjust models this way, and the mod works with the OptiFine model format as well.
To get a starting point, the mod can dump the models it has registered. After enabling the dump option in the second line of the configuration file and relaunching the game, the dumped files appear in a jsonem folder inside the game directory, formatted like a resource pack. A guide in the author text shows how to build a cube entity model with JSON, and the Java Entity Model file type in the editor can be used to start editing.
JsonEM is open source under the MIT License and runs on the client only, so servers do not need it. Fabric API is required on Fabric, and the mod is published for Fabric and Quilt across 21 release versions, 1.18 – 26.1.1, with snapshot builds included.
Key features
Data-driven entity models
Entity models are defined in JSON, so their shapes can be changed without rebuilding a mod.
Model dump
Registered entity models can be written out as JSON files that match the resource pack layout, as a base for editing.
OptiFine format support
Models can be written in the OptiFine format, which lets existing OptiFine-style models be used with the library.
Model tutorial
An included guide walks through building a cube entity model with JSON from start to finish.
Compatibility
Latest build for each game version and loader.
26.x1 of 1 version with builds
1.21.x5 of 5 versions with builds
1.20.x7 of 7 versions with builds
1.19.x5 of 5 versions with builds
1.18.x3 of 3 versions with builds
This mod also publishes snapshot builds. Snapshots are not shown in the matrix.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
How it compares
Mson is also a Fabric and Quilt library for JSON entity models, under the MIT License and open source, but it covers 1.20.5 – 26.3 and is client-side only. Json Entity Animation is a client-side only Fabric and Quilt option under the MIT License, open source, for 1.19.2 – 1.20.1, and focuses on animations. JsonEM covers 1.18 – 26.1.1 and is also client-side only and open source under the MIT License.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| JsonEM | Fabric and Quilt | 1.18 – 26.1.1 | Client-side only | 2026-04-16 |
| Mson | Fabric and Quilt | 1.20.5 – 26.3 | Client-side only | 2026-09-19 |
| Json Entity Animation | Fabric and Quilt | 1.19.2 – 1.20.1 | Client-side only | 2023-06-10 |
Questions
Does JsonEM need Fabric API?
Does a server need JsonEM installed?
Where are the dumped model files written?
Which loaders does JsonEM support?
In the catalog
JsonEM is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 11,522 mods support Minecraft 26.1.1.
More from FoundationGames
Similar mods
What the author says
Library for modders, resource pack makers, and modpack makers to create and edit entity models WITH JSON
Official listing
- Modrinth page
- modrinth.com/mod/jsonem
- Owner
- FoundationGames
- Published
- 2021-12-20
- Updated on Modrinth
- 2026-04-16
- Facts verified
- 2026-10-15