Simple player authentication mod for small Better than Adventure servers.
For server hosters
Create a folder named justauth in your server folder
For each player you want to give access to, create a file with their username and put a password in there (mashing your keyboard for like 5 seconds is generally a good idea. make sure to not go above 127 characters)
Copy this file, rename it to just.auth and share it with your friend
For players
- Your host will give you a file named just.auth, put it in your .minecraft folder
Tested on 7.3_03 but it's probably compatible with a whole bunch of other versions too!
Quick facts
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: b1.7.3
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
Verified by MCModsHub
- Ships as justauth-1.0.0.jar — drop this file into the mods folder
- Download size: 529 KB
- Download link checked 11 Sept 2026 — working
These come from our own check of the pack file, not from the source page.