Open-source Minecraft anticheat
Level up your players' experience.
Grim Anticheat simulates real client movement across Minecraft Java Edition versions 1.8-26.1, catching cheats without adding server lag.
Simulation first
Open source, precise by design
Rather than relying on bypassable tricks, Grim Anticheat simulates the client and does calculations using cold, hard math. Checks run on Netty threads for a seamless and lag-free experience.
Also supports Folia and MultiPaper.
Built for scale
What makes Grim different?
Grim accounts for every movement change across different Minecraft versions, from legacy 1.8 servers to modern 26.1 networks.
- Asynchronous movement processing
- Netty multi-threading
- Efficient world replication
- Highly efficient, small performance overhead
- Ground-breakingly precise player movement replication
- Lag compensation for all player interactions
The result is precise player replication that can keep up with networks of any size.
Server coverage
Supports the platformsserver owners actually run
Grim supports the platforms server owners actually deploy: Spigot, Paper and Paper forks, Folia, and Fabric. You can run the same movement simulation approach across traditional servers, region-threaded deployments, and modded Fabric environments.
Paper
Spigot
Folia
Fabric
