About GrimAC

GrimAC is an open-source Minecraft anticheat designed to keep your server secure while delivering a seamless, lag-free experience. Supporting Minecraft versions 1.8 to 1.21, GrimAC employs advanced techniques to detect cheats and exploits reliably.

Key Features

• Fully Asynchronous & Multithreaded
  All checks run on Netty threads, ensuring minimal performance impact even on large servers.

• Movement Simulation Engine
  Replicates every possible player movement—from walking and swimming to riding entities—while accounting for version differences.

• Full World Replication
  Maintains a per-player replica of the world for precise detection and lag compensation.

• Latency & Inventory Compensation
  Queues world changes until they reach the player and tracks inventory to reduce false positives.

• Cross-Version Compatibility
  Supports Minecraft 1.8 through 1.21 and works with Paper, Spigot, Folia, and more.

Installation & Requirements

• Java 17+ is required.
• For Bedrock support via Geyser, install Floodgate on your backend server.
• Download official builds from Modrinth.

Community & Contributions

GrimAC is maintained by a vibrant community and is free. Contributions, bug reports, and pull requests are welcomed on our GitHub repository.

Get Help

• Discord: Join our Discord server for support and discussions.
• Wiki: Find detailed documentation and examples on our Wiki.

Protect your Minecraft server with GrimAC—the anticheat solution that scales with your community while keeping gameplay fair and secure.

Grim Premium

Grim Premium is an optional paid service maintained by the official Grim team. This closed-source version has additional checks—including advanced heuristics—for even more robust protection. It’s designed for those who want to support the project and receive priority support. It’s currently not available for purchase but will be in the future.