TJAuth
by mstouk57g
TJAuth adds a password and whitelist check to Fabric servers, handled by an external authentication server that the server owner runs.
What it does
On connection, the client sends its UUID and username to the server, which then asks an external authentication server to verify the player against a whitelist or a password. The check can block clients that lack the mod, since the handshake relies on connection request packets, and a password input screen stays on the client until authentication completes. An auth timeout in seconds sets how long a client may stay inactive before it is kicked, and a server response that arrives after that window also counts as a timeout.
The external server is a separate program. The author provides ExampleAuthServer.py, which uses Python Flask, shows pass and fail paths with comments, and expects POST requests with application/json bodies. Signing keys can be generated with openssl, or the mod can generate them on its own. The mod supports Fabric 1.19.2 in its v1.0.0 build, and the designed tjmtr server works with Tianji Center.
Installation covers the server and each player's game. Fabric API is required. Files are published for Fabric only, across 1.19.2, 1.19.3 and 1.19.4, with 1.0.3-release+1.19.4 for 1.19.4 as the latest file. The code is under All rights reserved and is not open source.
Key features
External server authentication
Verifies players against a whitelist or password on an external authentication server, with configurable URLs and a server key.
UUID-based identity
Uses the real client UUID at startup, so offline players who share a username can be told apart.
Password input screen
A password prompt stays visible on the client until authentication is complete, and an empty value is not accepted.
Auth timeout
A configurable timeout in seconds controls how long a client can stay inactive before it is kicked.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Questions
Does TJAuth need Fabric API?
How are the signing keys made for the example server?
What the author says
An authentication module that can use an external authentication server to verify whitelists and passwords. This mod is designed for the tjmtr server and works perfectly with Tianji_Center.
Official listing
- Modrinth page
- modrinth.com/mod/tjauth
- Owner
- mstouk57g
- Published
- 2025-08-05
- Updated on Modrinth
- 2025-08-28
- Facts verified
- 2026-10-15