Citadel AC review
A free, configurable client-detection plugin for Paper servers on Minecraft 1.21.x.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Citadel AC is an open-source anti-cheat plugin for Minecraft Java Edition Paper servers running Minecraft 1.21.x. It is designed for server operators who want to identify known hacked clients, combat modifications, movement exploits, freecam, hacked menus, and unauthorized utility clients. Detection uses client signatures, translation keys, mod identifiers, and recognized cheat-client behavior, making the plugin particularly suited to servers focused on client detection rather than broad anti-cheat coverage.
Citadel AC is free and has no paid tiers. Its configuration is built around YAML, with a reloadable detection database and support for custom detection categories and responses. Server operators can configure automatic bans, kicks, or custom commands when detections occur. This gives the plugin a practical enforcement model for communities that want to adjust detection rules and responses without changing the core plugin.
The main trade-off is its narrow platform and detection focus. Citadel AC supports Paper servers on Minecraft 1.21.x, and its feature set centers on known client signatures, translation keys, mod identifiers, and related detection data. It has no integrations, so operators looking for a wider platform ecosystem may need another option. The small source repository and limited documentation may also require more interpretation during configuration. Choose Citadel AC for a free, open-source Paper server that prioritizes configurable known-client detection; choose an alternative if broader integrations or a less specialized anti-cheat approach matters more.
Citadel AC pros and cons
- Where it wins
- Free and open source under the GPL-3.0-only license
- Scans signatures, translation keys, mod identifiers, and behavior
- Supports configurable bans, kicks, and custom commands
- Where it doesn't
- Supports Paper servers running Minecraft 1.21.x
- Focuses mainly on known client and signature detection
- Small source repository with limited documentation
Citadel AC fact sheet, pricing and score →
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