GrimAC is an open source predictive antihack. This antihackis completely free at this time and there will be always an open source, 100% free version available.
The antihackis stable for both 1.8 and 1.19 servers with both versions being well tested. It is written for 1.19 and has been backported. Note that we don't fully support the 1.19.3 experimental datapack yet, it will result in undefined behavior.
There is a 1:1 simulation to the player's movements to prevent illegitimate actions. It detects 99.99% antikb, 0.0001% speed increases, and nearly any movement cheat tested on it. It can even detect Optifine FastMath in both reach and movement.
Geyser players are fully exempt.
For 3.01 reach please enable both pre and post transactions in the reach config, with 1.8 players on 1.8 servers. By default, pre and post transactions are disabled to save bandwidth. 1.9 players are checked to about 3.04 reach, with an extended fight.
Wiki: Commands, permissions, punishments, and more:
https://github.com/MWHunter/Grim/wiki
Installation notes:
If you use Geyser, place Floodgate on the backend server so grim can exempt bedrock players. Grim cannot access the Floodgate API if it is on the proxy.
If you use ViaVersion, it should be on the backend server as movement is highly dependent on client version.
The Anti Hack for Updated Versions Team
