What is YggUtils?
An overview of YggUtils, and what problem it solves.
YggUtils is a lightweight Java server wrapper that injects authlib-injector into any Minecraft server's JVM at launch — enabling custom Yggdrasil authentication on hosting environments where you cannot set JVM arguments directly.
Just want to get running?
Head to the Getting Started page.
The Problem It Solves
Most Minecraft hosting panels don't let you modify JVM startup flags. Running a private network with a custom auth server normally requires adding a -javaagent flag to the JVM — something many shared hosts simply don't expose.
YggUtils wraps your server JAR and handles the agent injection itself, so you only need to run one JAR.
Key Features
Authlib Injector Fetching
Downloads and manages authlib-injector.jar automatically. No manual installation required.
Simple Configuration
A single YAML file controls which auth server and JAR to use. No interactive setup prompts.
Auto-Restart
Detects crashes via non-zero exit codes and relaunches the server after a 3-second delay.
Silent Operation
No wrapper noise in your console. Server output is passed through exactly as produced.
What YggUtils Is Not
YggUtils is not an authentication server. It does not implement the Yggdrasil API itself — it simply redirects your Minecraft server's auth calls to whichever backend you configure. You will need a separately hosted Yggdrasil-compatible auth server.