Grim Anticheat
ModA server-side tool that catches players using cheats.
Why gradeA
How grades workStrengths
Points lost
No points lost.
All 11 criteria
Maintenance
Full points27 / 27Last releaseHow long ago the newest file came out, or an existing file was marked as working on a new Minecraft version.Yesterday (23 Oct 2026) 12 / 12Supports popular versionsWhether the project has a file for a Minecraft version that 15% or more of the popular mods updated in the last 6 months also support. A version many modpacks use, like 1.20.1 or 1.21.1, also counts after a release in the last 12 months.26.3 on Fabric (latest) 9 / 9Regular releasesIn how many of the last 24 months a new file came out. Full points at 8 months.Releases in 19 of the last 24 months 6 / 6Stability
Full points22 / 22Removed from modpacksHow many modpacks removed it in a later version of the pack. We can only see this in modpacks with two or more versions. A pack that swaps it for another edition of the same project, or that is rebuilt from scratch, does not count.2 of the 3 modpacks with two or more versions removed it in a later one (67%) 10 / 10Quick fixesHow often a release needed a quick fix: a new release within 3 days to fix a problem in it.Not counted: it puts out releases very often, so quick fixes are normal for it 7 / 7Known conflictsHow many projects say they do not work with it, compared with how widely it is used. Packs, small projects, forks, ports, add-ons, alternatives and old versions do not count.None 5 / 5Transparency
Full points10 / 10Source codeWhether the project page links to its source code, so anyone can read what it does.GitHub · GrimAnticheat/Grim 7 / 7Place to report problemsWhether the project page links to a place where players can report problems: an issue tracker.GitHub issues · GrimAnticheat/Grim 3 / 3Popularity
Full points4 / 4DownloadsDownloads on Modrinth and CurseForge. Full points from 5 million.806,774 4 / 4Track record
Full points8 / 8AgeHow long the project has existed. It counts less when no new file came out recently.2.2 years, 884 releases 8 / 8Security
PassedFile checksThis check adds no points. It can only take points away.Our checks found nothing harmful in both latest files for recent Minecraft versions. See Security
70.5 of the 71 points that apply = 99 out of 100. The points above are rounded to whole numbers.
About
GrimAC is an open-source server anticheat that detects and reports cheating by checking player actions against expected Minecraft behavior. Its movement engine simulates the movements available to each player, covering actions such as walking, swimming, knockback, web and bubble-column movement, and riding boats, pigs, or striders while accounting for version-specific collisions and block behavior. Grim keeps a separate replica of the world for each player and compensates for latency by queuing world changes until they reach that player; it also tracks inventory state to help avoid false flags from lag-related ghost blocks and other errors. Its checks cover movement, reach, falling, timers, knockback, slow movement, scaffolding and block placement, as well as suspicious packets and crash attempts. Designed to run movement checks and most listeners asynchronously across multiple threads, Grim can scale to servers with many hundreds of players. Staff can review alerts, player profiles, detailed flags, debug output, and stored violation and session history, while configuration lets server operators group checks and set alert or command actions for violations. Grim is not intended to ban players automatically by default; operators can configure responses to violations, including alerts, kicks, and other commands. It supports Bukkit-based servers, Folia, and Fabric, and provides a plugin API for integrations with other plugins.
Written from Modrinth . How we write it
In-game changes
Changes the game's code in 5 areas, as a library other mods build on: Networking and multiplayerChanges 5 game code files in this area: connections, the server list and what is sent between your game and a server., Server and world logicChanges 5 game code files in this area: the world, commands, scoreboards, saved data and game rules., PlayerChanges 4 game code files in this area: your character: movement, abilities, hunger and controls., Chunk loading and storageChanges 2 game code files in this area: how the game loads, tracks, saves and unloads chunks. and Mobs and their behaviorChanges 2 game code files in this area: mobs, animals, villagers, projectiles and how they move and act..
Libraries packed inside it change 4 more game code files: Cloud.
Adds no new blocks, items or other content.
Keeps all of vanilla Minecraft's textures, models and sounds.
Details
Security
No harmful code found
We checked its files and read their code, without running it.
What it can do on your computer
- Connects to Discord
- The code contains a Discord webhook, an address that receives messages. Found in GrimAC, a library it includes and in GrimAC (Fabric, official mappings), a library it includes.
- Connects to the internet
- It has code that can go online, for example to check for updates, load skins or send crash reports. Found in 4 libraries it includes. See Privacy
- Creates settings files
- The mod keeps its settings in the config folder of your game, where you can change or delete them. 11 files in your config folder.
Why we show this: a mod runs on your computer like any program, so harmful code in it can take your accounts or files. Our checks look for known signs of harm. They cannot prove that a file is harmless. In the grade: malware means no grade, and a Warning in a latest file for a recent Minecraft version lowers it.
How we checked
- FilesWe download the files from Modrinth or CurseForge and look at what is inside them and what their code can do, without running them. Fixed rules tell what is harmful.2 latest files: the newest file for each Minecraft version and loader. Both are for recent versions. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks. See each file in Releases
- Their codeWe turn the code of the files back into readable code and follow what it does, without running it. This shows what it downloads, what it sends and where your login goes.Read without running it
- Author on ModrinthThe disclosure form on Modrinth, where the author declares that the project reads or edits things on your system outside the game. Since 13 Aug 2026, Modrinth's rules require it when this applies.Nothing declared about your system outside the game.
- Looked for, not foundWe looked for these in the file and did not find them.Folders outside the game, other programs, updating itself, the webcam or microphone, an AI service.
Privacy
Sends usage statistics and unknown data
Sent to bstats.org and an address built while the game runs.
Only some of its files send unknown data.
We found this in its code, read without running it.
The author declares on Modrinth that it sends crash reports or usage data unless you turn this off.
Why we show this: a mod can send things about you over the internet, like your player name or your login. Contacting an address to check for updates or download files sends nothing about you. Not in the grade: sending data can be normal for what a mod does.
How we checked
- Files readWe read the code without running it. We list each web address the code contacts while you play, and what it sends. Code that is never used is left out.The code of both files, for recent Minecraft versions. See each file in Releases
- bstats.orgSends usage statistics.Usage statistics
- api.github.comChecks for a new version of the mod.From a bundled library.Nothing about you
- Address built while the game runsThe code builds this address while the game runs: it is not written in the file.Checks for a new version of the mod.Unknown data
- Named in its filesA crash report or usage data service named in the files of the mod. The code does not show when or what is sent.The code names bStats, a service that receives usage data.
AI
AI was used for its code
The author declares AI code on Modrinth.
We looked for AI tools in its texts, files, images and code history and found none.
One weak clue: a branch is named like those Codex creates. It does not show that the tool was used.
No sign of AI in the game
We found no AI service, AI library or AI model file in its code.
Why we show this: some players and servers avoid projects made with AI, and AI in the game can send what you write to an online service. Not in the grade: using AI does not tell whether a project works well or is kept up to date.
How we checked
- Author on ModrinthThe disclosure form on Modrinth. Since 13 Aug 2026, Modrinth's rules require it when a substantial part of the code is AI output, when an asset is mainly AI output, or when the project or its page relies on generative AI.Declares AI code. No AI features declared.
- Code historyThe public code on GitHub: who made each change, credit lines such as "Co-authored-by", and its files.Weak signA branch name only. It does not show that the tool was used.: A branch named like those Codex creates
codex/history-async-storage-stack - Description and changelogsThe description, project page and newest changelogs: sentences saying an AI tool was used, and text pasted from an AI chat.Nothing found20 changelogs read
- Its filesFiles that AI coding tools leave behind (like AGENTS.md), and the texts inside the files you download.Nothing found
- Images in its filesHidden data in the images of the files you download, where AI image tools write their name and settings.Nothing found
- Code of the modThe code and files of the mod, read without running it: addresses of AI services, AI libraries, AI model files and a place for your own AI key.No AI service, AI library or AI model file28 code files read
Compatibility
See all 884 filesPoint at or tap a version to see its loaders.
Modpacks using this project
Find modpacks with itModpacks that include Grim Anticheat in at least one of their versions, most downloaded first.
Serverside Anticheat1.9K downloadslast version with it 12 Jul 2026
Reload Again1.6K downloadslast version with it 29 Aug 2026
ChosenCraft V2796 downloadslast version with it 12 Jul 2026
Better Server Side338 downloadslast version with it 13 Dec 2025
Glatzencraft329 downloadslast version with it 10 Jul 2026
1st Arternic Games112 downloadslast version with it 8 Jul 2026Latest files
The newest file for each Minecraft version and loader. The files for recent versions come first. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks.