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MinecraftOfflineOnlineConverter

A simple Java application to convert Minecraft server player files between online and offline mode.

Install / Use

/learn @paul-eff/MinecraftOfflineOnlineConverter
About this skill

Quality Score

0/100

Supported Platforms

Universal

README

MinecraftOfflineOnlineConverter v3.1.1

<p align="center"> <img src="https://img.shields.io/badge/version-3.1.1-blue"> <img src="https://img.shields.io/badge/minecraft-1.21.11-green"> <img src="https://img.shields.io/badge/java-21-red"> </p>

Ever started playing on one of your Minecraft servers and a few hours later that one friend that didn't buy the game wants to join? Now you have to start a lengthy process of turning your server to offline mode and making sure everyone has their inventory and achievements after the switch...

This happened to me way to often, and now I automated the whole process. The Java applicatin will convert all player related files to be offline or online compatible.

Supporting

[!WARNING]
As of Minecraft version 26.1 there were some changes to world folder structure! This means I currently can't guarantee that the plugin will work as intended. I am on it, but this can take a bit. Cheers!

Currently I tested and can confirm support for Vanilla, Bukkit, Paper and Purpur servers. Every Minecraft version since and including 1.17.1 is confirmed to work. Earlier versions I can't guarantee.

Regarding Spigot and Forge servers, I haven't had enough time to fully confirm everything will work 100% of the time. But using the new mooc-config.yml file, you can specify custom directories to convert.

Usage

First look at Disclaimer and make sure you understand the "risks" of using this tool.

  • Download the most current jar

  • Place it in your server's main folder (not mandatory, just makes things easier)

  • Optional: Rename TEMPLATE.mooc-config.yml to mooc-config.yml and use the examples presented to define custom directories you want to convert

  • Execute the jar through your terminal with the following command:

java -jar MinecraftOfflineOnlineConverter.jar <arguments>
  • You will have to pass one of these arguments
    • -offline to convert your server to offline files
    • -online to convert your server to online files
  • If necessary -p "path/to/server/folder/" (if the jar is not in the server's main folder)
  • -c to copy player data from one world to another
  • -properties to directly edit values in server.properties
  • -v for verbose output
  • -h for help

Known Issues

  • Paper servers (when converted to offline), sometimes create <Online UUID>.dat.offline-read) files.
  • No full support for Spigot, Sponge and Forge servers.

Building

Execute the command

mvn clean compile assembly:single

to build a JAR file of the project with all dependencies.

Disclaimer

Please always make a backup of your game files before using this tool. Whilst it was thoroughly tested on my own servers, there is always the chance that a bug might occur!

If you need this application for a lower Minecraft and/or Java version, please leave me a message or issue :)!

License

This project is licensed under the MIT License.

Remark

Minecraft is a registered trademark of Mojang AB.

View on GitHub
GitHub Stars60
CategoryDevelopment
Updated2d ago
Forks1

Languages

Java

Security Score

100/100

Audited on Apr 5, 2026

No findings