KrepAPI (Mod)
by ShinKuyomi
KrepAPI is a Fabric library that gives a client a bridge to multiplayer servers running matching server-side code, through custom key bindings and a handshake.
What it does
The library lets a server and a Fabric client exchange custom key bindings and raw key input. Plugin messages carry a small binary protocol between the two sides, and the handshake checks the protocol version and the KrepAPI build before the connection is accepted. A server can be set to disconnect clients that are missing the mod or that run a mismatched build, so policy is enforced at login.
Installation is needed only on the servers and clients that use KrepAPI. Fabric API is required, and a single jar can serve as the protocol handler on a Fabric dedicated server. Servers on Paper or Spigot can use it through a plugin, and reference implementations, documentation and a sample plugin are in the project repository. KrepAPI is published for Fabric only, across the game versions 1.21.4 – 26.1.1, and is open source under the Apache License 2.0.
Key features
Custom key bindings
Mods built on the library can define extra key bindings that the client syncs with the server.
Raw key input hooks
Client code can react to raw key input, so add-ons are not limited to the standard binding system.
Protocol handshake
The handshake verifies the protocol version and the mod version before the connection continues.
Server connection policy
Servers can disconnect misconfigured or missing clients according to their policy.
Compatibility
Latest build for each game version and loader.
26.x2 of 2 versions with builds
1.21.x8 of 8 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Who it’s for: Developers building Fabric client mods that need server coordination, and server owners who run matching server-side code. Players gain nothing from it alone.
How it compares
Modded Creative Menu is a Fabric mod under the GNU Lesser General Public License v3.0 only, open source, for 1.21 – 26.2, and it targets creative inventory rather than server sync. Dimension Bridge is also Fabric and open source, under the GNU Lesser General Public License v3.0 or later, for 1.20.1 – 26.2. BukkitFabricLoader is server-side only, under the MIT License, is not open source, and covers 1.21 – 1.21.11, so it bridges Bukkit plugins to Fabric instead. Multi Key Bindings is client-side only, open source under the GNU General Public License v3.0 only, and covers 1.20 – 26.3.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| KrepAPI (Mod) | Fabric | 1.21.4 – 26.1.1 | Client-side only | 2026-04-11 |
| Modded Creative Menu | Fabric | 1.21 – 26.2 | Not published | 2026-08-22 |
| Dimension Bridge | Fabric | 1.20.1 – 26.2 | Not published | 2026-07-26 |
| BukkitFabricLoader | Fabric | 1.21 – 1.21.11 | Server-side only | 2026-02-15 |
| Multi Key Bindings | Fabric | 1.20 – 26.3 | Client-side only | 2026-09-16 |
Questions
Does KrepAPI need Fabric API?
Does a single-player world need KrepAPI?
Which game versions does KrepAPI support?
In the catalog
KrepAPI (Mod) 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.
Similar mods
What the author says
KrepAPI is a Fabric mod that lets multiplayer servers (via Paper/Spigot plugin messages or a Fabric server with the same protocol) define extra key bindings on your client, react to raw key input when allowed, and optionally require that you have this mod installed. You only need KrepAPI if the server you play on…
Official listing
- Modrinth page
- modrinth.com/mod/krepapi
- Owner
- ShinKuyomi
- Published
- 2026-04-03
- Updated on Modrinth
- 2026-04-11
- Facts verified
- 2026-10-15