κoωo (kowo-lib)
κoωo (kowo-lib) is a Java library for Fabric and Quilt that builds UI components with a Kotlin-friendly syntax, and is used by other mods that need custom screens.
What it does
Developers write interface code in a concise style: a child component can be added to a parent in one call, and the library offers a Kotlin syntax that reads more cleanly than the plain builder calls. A set of examples in the repository shows how the pieces fit together.
Screens can be styled with MSS, the Minecraft Style Sheets format, so colors, sizes and spacing are kept out of the layout code. Because it is a library, nothing appears in the game until another mod uses it, and the mod is published for 1.20.5 – 1.21.8 on Fabric and Quilt. Fabric API, Fabric Language Kotlin and oωo (owo-lib) are required dependencies.
Client and server both need the library, since the same classes run on each side. Files cover 1.20.5, 1.20.6, 1.21, 1.21.5, 1.21.6, 1.21.7 and 1.21.8, and the code is open source under the MIT License, with a public source repository and issue tracker.
Key features
Kotlin-friendly syntax
A Kotlin syntax layer lets interface code be written more compactly than with the standard Java builders.
Parent and child components
Adding a child component to a parent takes a single call, which keeps nested layouts short to write.
Style sheets
Components can be styled with MSS, so appearance rules live in a separate sheet from the layout logic.
Example code
The project ships with examples that demonstrate the common patterns for building screens with the library.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 3
How it compares
Silk API is a Fabric and Quilt library for 1.20 – 1.21.1 under the GNU Lesser General Public License v3.0 only, and it runs on client and server. Fancy Entity Renderer covers Fabric, Forge and NeoForge for 1.20.1 – 26.2 under the GNU General Public License v3.0 or later, and it is client-side only. Quilt Kotlin Libraries (QKL) targets Quilt alone for 1.19 – 1.21 under the Apache License 2.0, and it is optional on either side.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| κoωo (kowo-lib) | Fabric and Quilt | 1.20.5 – 1.21.8 | Client and server | 2025-05-10 |
| Silk API | Fabric and Quilt | 1.20 – 1.21.1 | Client and server | 2024-11-19 |
| Fancy Entity Renderer | Fabric, Forge and NeoForge | 1.20.1 – 26.2 | Client-side only | 2026-10-10 |
| Quilt Kotlin Libraries (QKL) | Quilt | 1.19 – 1.21 | Client or server, optional | 2024-10-11 |
Questions
Does κoωo need Fabric Language Kotlin?
Do servers need κoωo installed?
Which loaders does κoωo support?
In the catalog
κoωo (kowo-lib) is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 17,695 mods support Minecraft 1.21.8.
More from Bonfire Studios
Similar mods
Official listing
- Modrinth page
- modrinth.com/mod/kowo-lib
- Owner
- Bonfire Studios
- Published
- 2024-05-23
- Updated on Modrinth
- 2025-05-10
- Facts verified
- 2026-10-15