# GrimAnticheat/Grim

Fully async, multithreaded, predictive, open source, 3.01 reach, 1.005 timer, 0.01% speed, 99.99% antikb, "bypassable" 1.8-1.21 minecraft anticheat.

Repository: https://github.com/GrimAnticheat/Grim
Canonical: https://ross.abutalabs.com/products/grim
Homepage: https://grim.ac
Language: Java
License: GPL-3.0
License Family: copyleft
Topics: anticheat, minecraft, fabric, bukkit, java, minecraft-plugin, papermc, spigot, spigot-plugin, spigotmc, folia, paper-plugin, grim, bukkit-plugin, paper, folia-plugin
Last push: 2026-08-26T19:40:17+00:00

## Health v2 (maintenance only)
Score: 82/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 50, longevity 100
- inputs: {"age_days": 2019, "days_push": 7, "days_rel": 177, "gap_med": 157, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1724, forks 636 (observed 2026-08-28T04:05:27.969264+00:00)

## What it is
GrimAC is an open-source Minecraft anticheat plugin that detects cheats by simulating real client movement with fully asynchronous, multithreaded checks running on Netty threads. It supports Minecraft Java Edition 1.8 through the latest versions on Spigot, Paper, Folia, and Fabric servers.

## Use cases
- stop cheaters on my minecraft server
- detect reach hacks and killaura
- block speed and timer cheats
- anticheat that doesn't cause server lag
- protect a paper or folia server from movement cheats
- open source anticheat for minecraft 1.8 through latest
- reduce false positives for bedrock players via geyser

## When to choose
- you run a Spigot, Paper, Folia, or Fabric Minecraft server and need precise, low-overhead cheat detection
- you want an open-source anticheat with movement simulation rather than heuristic checks
- your server supports multiple Minecraft versions from 1.8 to the latest release
- you need lag compensation and low false positives for latency or inventory interactions

## When to avoid
- you need Bedrock/Geyser player checks - Geyser players are fully exempt
- you want heuristic or behavioral cheat detection - that is planned for the paid premium version
- you run ViaVersion on your proxy rather than the backend server
- your server runs on Java below version 17

## Facets
- artifact type: plugin
- maturity: active
- function: security, monitoring, middleware
- domain: gaming-tools, security, developer-tools
- platform: jvm, self-hosted
- tags: anticheat, movement-simulation, bukkit-plugin, paper-plugin, fabric-mod, spigot, folia, netty, cheat-detection, minecraft

## Member repositories
- GrimAnticheat/Grim (main) score 82

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:27.969264+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:33:53.674351+00:00, confidence not recorded.
  - readme: https://github.com/GrimAnticheat/Grim (fetched 2026-08-28T04:05:27.969264+00:00, sha 7774bc9ef6af)
  - homepage: https://grim.ac (fetched 2026-08-29T11:09:15.973706+00:00, sha d432e5f134a6)
  - site_page: https://grim.ac/page/about (fetched 2026-08-29T11:09:15.982343+00:00, sha 284e4067186c)
  - site_page: https://grim.ac/page/docs (fetched 2026-08-29T11:09:15.984173+00:00, sha 612ef4eda0e1)
- Data as of 2026-08-30T08:39:29.467469+00:00.