This is a community fork maintained by SharkMI, based on CardboardPowered/cardboard.

It includes additional compatibility fixes that have not yet been merged upstream.

🐛 Issues & Feedback

• Fork-specific bugs or suggestions → Please open an Issue in this repository.
• General discussion or questions → Feel free to join the Cardboard Discord (the upstream community).

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Fork Differences

This is a fork of the official Cardboard project with the following changes:

• Enhanced mixin compatibility: Replaced @Overwrite annotations with precise injection methods (@Inject, @ModifyArg, @Redirect) to avoid conflicts with other Fabric mods
• MiniMOTD compatibility: Fixed server status ping conflicts with MiniMOTD mod
• carpet-tis-addition compatibility: Fixed boat item placement conflicts
• Fabric API NPE fix: Resolved crash caused by Fabric API field injection timing
• OWASP security scanning: Integrated OWASP Dependency-Check into the build pipeline
• Mixin conflict detection tool: Built-in runtime scanner that detects mixin conflicts across all loaded mods at startup (6 detection rules, FATAL/HIGH/MEDIUM/LOW severity levels, console + JSON report output, optional auto-disable for fatal conflicts)

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Overview

Cardboard is an implementation of the Bukkit/Spigot/Paper API for FabricMC. It allows you to run plugins from the Bukkit ecosystem on a Fabric modded server, giving you the best of both worlds: mods and plugins.

Features

• Support for Bukkit/Spigot/Paper plugins
• Full Bukkit API implementation (work in progress)
• NMS (net.minecraft.server) support with automatic remapping
• Compatible with Fabric API
• Mojang official mappings

Installation

Prerequisites

Software	Version
Java	21+
Fabric Loader	0.16+
Minecraft	1.21.1+

Steps

1. Install Fabric Server

   • Download the Fabric Installer
   • Or use the Fabric Server Installer

2. Download Cardboard

   • Get the latest jar from the official website or GitHub Releases

3. Place in mods folder

   server/
   ├── mods/
   │   ├── cardboard-xxx.jar    <-- put here
   │   └── fabric-api-xxx.jar   <-- Fabric API (required)
   ├── eula.txt
   └── server.properties
   

4. Start the server

   • The config file will be generated automatically on first launch
   • Place plugins in the plugins/ folder

Usage

Loading Plugins

Simply drop .jar plugin files into the plugins/ directory and restart the server.

Configuration

Configuration file is located at config/cardboard/cardboard-config.yml:

# Enable automatic conflict resolution
auto-conflict-resolution: true

# Force-disabled mixins (for resolving conflicts)
mixin-force-disable: []

# Mixin conflict detection
runtime-conflict-scan: true
conflict-scan-json-output: false
auto-disable-fatal-conflicts: false

# Debug options
debug-print-event-call: false
debug-print-all-calls: false

For detailed conflict detection configuration, see docs/mixin-conflict-detection/user-guide.md.

Building

Requirements

• Java 21+
• Gradle (wrapper included, no extra installation needed)

Build Commands

# Windows
.\gradlew.bat build

# Linux/Mac
./gradlew build

# Skip tests (faster)
.\gradlew.bat build -x test

Build artifacts are located in build/libs/.

Version Support

Minecraft Version	Fabric Version	Branch	Status
1.21.11	0.16+	ver/1.21.11	Active
<= 1.21.8	-	-	No Longer Supported

This fork focuses exclusively on the latest Minecraft version. Older versions are not maintained. See Supported Versions for upstream details.

Plugin Compatibility

Tested Working

Plugin	Status	Notes
EssentialsX	Partial	Core features work
WorldEdit	Partial	Basic operations work
Vault	Experimental	Economy system integration
LuckPerms	Experimental	Permission system

Known Incompatibilities

Plugin/Mod	Reason	Workaround
Some mods using Mixin	Injection point conflicts	Disable conflicting mixins in config

Known Issues

• Mixin Conflicts: Some Fabric mods using @Overwrite may conflict with Cardboard
  • Solution: Configure mixin-force-disable in cardboard-config.yml
• NMS Plugins: Some plugins deeply dependent on NMS may not work
  • Cardboard supports automatic NMS remapping, but coverage is not 100%
• Missing Events: A few Bukkit events are not yet implemented

Contributing

We welcome contributions of all kinds.

Reporting Bugs

1. Search Issues for existing reports of the same problem
2. If not found, create a new issue with:
   • Server log (latest.log)
   • Cardboard version
   • Steps to reproduce

Submitting Code

1. Fork this repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'feat: add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Create a Pull Request

Development Guidelines

• Follow Conventional Commits specification
• Use English for code comments
• Use @Inject instead of @Overwrite for new mixins

Documentation

Note: Comprehensive documentation for this fork is still being written. For now, refer to the upstream resources below.

• Wiki
• API Javadoc
• Supported Bukkit Versions
• FAQ

Credits

• BukkitTeam, Spigot, and Paper for their work on the API
• Glowstone for the library loader
• md_5's SpecialSource, SrgLib by Techcable & Orion, MinecraftMapping by Phase
• All Cardboard contributors
• All SharkMI fork contributors
• Trae SOLO and OpenCode for AI-assisted development

License

This project inherits the license from Paper. See Paper's License for full details. SrgLib is licensed under MIT.

This project is licensed under the GPL-3.0 License. See LICENSE for details.