Kappa
by hibi
Kappa is a Fabric client mod that adds OptiFine capes to Minecraft without altering the vanilla cape code it relies on.
What it does
Kappa adds support for OptiFine capes. It hooks into the cape logic in a narrow way, so vanilla cape behavior is changed as little as possible. Because the mod touches only a small part of the game, it is meant to stay out of the way of other mods and of server moderation tools.
The mod runs on the client alone, and only the player who installs it needs it. Kappa is published for Fabric across 12 release versions, 1.17 – 1.20.1, with 3.0.4 for 1.20.1 as the latest file. Snapshot builds are published too. Quilt support is included, and the mod uses few Fabric-specific components, which the author notes as a way to keep porting simple. The code is released under The Unlicense, so the project is open source.
Kappa sits in a gray area of Minecraft's commercial usage guidelines, because OptiFine's own capes already fall there. The author notes this and suggests that Quilt users may prefer to avoid it. The project's source code and issue tracker are both public.
Key features
OptiFine cape support
Players can display OptiFine capes in the game, with the cape logic modified only where needed.
Minimal vanilla changes
Instead of cloning vanilla cape code, the mod hooks into it, so most of the cape system stays untouched.
Snapshot testing
The author tests the mod against the latest snapshot, since OptiFine capes can break after game updates.
Compatibility
Latest build for each game version and loader.
1.20.x2 of 2 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
This mod also publishes snapshot builds. Snapshots are not shown in the matrix.
Use cases
Who it’s for: Players who already use OptiFine capes on Fabric and want them in the game. The mod is client-side only, so server owners do not need to install it.
How it compares
OF Capes is a Fabric client mod for 1.19 under the GNU Lesser General Public License v2.1 only, and it is open source. Capes covers Fabric and Forge for 1.17 – 26.3, is client-side only, and is also open source under the same license. Optifine Capes Reborn is a Fabric client mod for 1.21 – 26.3 with a proprietary All rights reserved license, so it is not open source.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Kappa | Fabric | 1.17 – 1.20.1 | Client-side only | 2022-10-26 |
| OF Capes | Fabric | 1.19 | Client-side only | 2022-07-20 |
| Capes | Fabric and Forge | 1.17 – 26.3 | Client-side only | 2026-09-16 |
| Optifine Capes Reborn | Fabric | 1.21 – 26.3 | Client-side only | 2026-10-01 |
Questions
Does Kappa need to be installed on the server?
Which Minecraft versions does Kappa support?
Is Kappa safe to use with Quilt?
More from hibi
What the author says
Kappa adds OptiFine capes (correctly), and is aimed for use in snapshots. It's also meant to be very light and to modify very little so it doesn't upset server moderators, or so it doesn't get broken very easily (which upsets me!). Kappa is not like other mods! It works smart, not hard! Usually mods just clone the…
Official listing
- Modrinth page
- modrinth.com/mod/kappa
- Owner
- hibi
- Published
- 2021-06-08
- Updated on Modrinth
- 2022-10-26
- Facts verified
- 2026-10-15