KotlinMCUI
by 2894638479
KotlinMCUI is a GUI library for Minecraft mod developers that lets interfaces be written with a Kotlin DSL instead of raw widget code.
What it does
Interfaces are described in Kotlin, with a declarative and responsive layout system that arranges elements as the screen size changes. Scaling is context-aware, so components adjust to the surrounding container rather than to fixed pixel values. The default look follows vanilla UI styling, which keeps custom screens visually close to the rest of the game.
The library is a client-side tool. It is published for Fabric, Forge and NeoForge across 47 release versions, 1.14 – 26.2, and the MIT License applies to its source, which is open source. Its required companion is KotlinMCUI-backend, which must be installed separately, and the Kotlin language support comes from Fabric Language Kotlin on Fabric or Kotlin for Forge on Forge, both optional entries in the metadata.
Blue Archive Halo, KotlinMCUI-backend and KotlinMCUI-Backend (Port) are the other catalog mods that declare a dependency on this library. The single jar is meant to run on every listed loader without a separate build per platform.
Key features
Kotlin DSL interfaces
Screens are built with a Kotlin domain-specific language, using a simple syntax for placing and nesting elements.
Declarative responsive layout
Elements are positioned by declared rules that respond to changes in window size, instead of hand-placed coordinates.
Context-aware scaling
Sizes adjust relative to the surrounding context, so nested components keep their proportions.
Vanilla UI style
The default styling matches the look of standard Minecraft screens, so custom interfaces sit comfortably beside vanilla ones.
Cross-platform entrypoint
One entrypoint covers every supported loader, so a single jar serves Fabric, Forge and NeoForge.
Gallery
Compatibility
Latest build for each game version and loader.
26.x4 of 4 versions with builds
1.21.x12 of 12 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
1.17.x2 of 2 versions with builds
1.16.x6 of 6 versions with builds
1.15.x3 of 3 versions with builds
1.14.x5 of 5 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Optional 2
Required by 3 mods
Use cases
Building custom settings screens
A mod author can describe a configuration screen in a few lines of Kotlin and rely on the layout system for sizing.
Who it’s for: Mod developers who want to build graphical interfaces in Kotlin on Fabric, Forge or NeoForge, and who are prepared to install the required backend alongside the library.
Questions
Does KotlinMCUI need KotlinMCUI-backend?
Which loaders does KotlinMCUI support?
Does KotlinMCUI have to be installed on servers?
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What the author says
A GUI lib powered by kotlin DSL. It's designed to support all minecraft versions and loaders.
Official listing
- Modrinth page
- modrinth.com/mod/kotlinmcui
- Owner
- 2894638479
- Published
- 2026-02-02
- Updated on Modrinth
- 2026-07-14
- Facts verified
- 2026-10-15