VoidAC

!(https://cdn.modrinth.com/data/cached_images/6f624a99defd10b20af28bd4e64c743a2e3cc7c8.png)

VoidAC is a prediction-based anticheat that simulates every possible player movement server-side. If a player moves in a way that is mathematically impossible, they get flagged - no heuristics, no guessing.

It is a fork of (https://github.com/GrimAnticheat/Grim) and is completely free and open source under the GNU GPL v3.

• --
• ## Discord / Support

Join the community for support, false positive reports, and updates.

[!(https://img.shields.io/badge/Discord-Join-5865F2?style=flat&logo=discord)](https://discord.gg/e7WffFM6k3)

## What it catches

| Category | Checks | |----------|--------| | Movement | Speed, Flight, Jesus, NoFall, Timer, Phase, Glide, Blink | | Combat | Reach, Hitbox expansion, Aim assist, AutoClicker, AutoTotem | | World | Scaffold/Tower, FastPlace, NoSlow, Baritone (auto-walk) | | Packets | BadPackets, PacketOrder, TimerLimit, AntiSpoof (fake client) | | Exploit | Freecam, MultiActions, Vehicle hacks, Elytra exploits |

Geyser/Bedrock players are always exempt - no Bedrock false positives.

## Why VoidAC

Simulation engine - mathematically verifiable, not pattern-based. Speed hacks and flight are impossible to sneak past due to a 1:1 movement replication engine (covers everything from basic walking/swimming to riding entities). Low false positives - the engine accounts for lag, ViaVersion, ViaBackwards, ping spikes, Optifine FastMath, and many other quirks. Latency & inventory compensation - tracks inventory to prevent ghost blocks and queues world changes (like breaking blocks under players) until they reach the client, avoiding false flags. Full world replication - maintains a compressed world cache (16-64 kb per chunk) per player to allow safe multithreading, prevent issues with client-side or fake blocks, and eliminate block glitching falses. No license key required - drop the JAR in and it works. Multi-version & cross-version accuracy - one JAR covers 1. 8 clients all the way to 26. 1, accurately handling client/server translation, missing blocks, correct collision orders, and minor bounding box changes across versions. Folia support - runs natively on threaded-region servers. Lightweight & asynchronous - all movement checks, the world cache, and the majority of listeners run entirely on the netty thread. Carefully designed for thread safety without main-thread overhead, scaling to hundreds of players.

## Punishment system

VoidAC has a built-in punishment pipeline - no extra plugins needed (though LiteBans is supported for tempbans).

• Auto-punish - kicks or bans automatically once a player hits a violation threshold. Configurable per-check.
• Manual punish - `/void punish ` with a customizable ban screen.
• Ban wave - queue suspicious players and ban them all at once with a single command. Great for catching ban evasion.

## Anti-Xray & StorageESP

VoidAC can configure Paper's built-in anti-xray engine automatically on startup. It also supports Storage ESP decoys - fake chest/barrel/shulker packets are sent to clients to confuse X-ray mods that reveal storage blocks.

Both features are opt-in and configured in `config.yml`.

## Threshold Optimizer

VoidAC includes an adaptive threshold tuning system that learns from real server data to automatically recommend optimal violation thresholds. This eliminates guesswork when configuring punishments.

How it works: 1. Run `/void optimizer start` to begin collecting flag data 2. Grant trusted/legit players the `void.optimizer.legit` permission - their flags are treated as false positives 3. Let the server run for 24+ hours with active gameplay 4. Run `/void optimizer stop` then `/void optimizer save` to generate recommendations 5. Review the generated `threshold-optimizer-report.yml` and apply thresholds to `punishments.yml` manually

Key features: - Safety multiplier - recommends thresholds at 1. 5× the highest legitimate flag to avoid false positives - Per-check analysis - each check gets independent recommendations based on actual player data - Minimum sample validation - ignores checks with fewer than 5 legit samples (insufficient data) - Lightweight - minimal CPU overhead; the optimizer is designed to run continuously

Available commands: - `/void optimizer start` - begin collecting flag data - `/void optimizer stop` - stop collection (required before saving) - `/void op