Server Documentation

Server Setup

Everything you need to run a Minecraft server with full Leather Client support — offline routing, auto-login, and the auth bridge plugin.

Overview

Leather Client connects to standard Minecraft servers without any changes. However, to unlock auto-login and offline session routing, you'll need to install the leather-auth-bridge plugin on your server.

Once installed, players using Leather Client will be authenticated automatically on join — no password prompts, no credential screens.

Requirements

  • Server software: Paper, Spigot, or Bukkit (1.19+)
  • Java: Java 17 or higher
  • Leather Client: v1.0.0 or later on the player's machine
Vanilla servers are supported for standard play but won't support auto-login without the plugin.

Installation

  1. Download the leather-auth-bridge.jar plugin below.
  2. Drop the file into your server's /plugins folder.
  3. Restart the server. A config file will generate at /plugins/LeatherAuth/config.yml.
  4. Edit the config as needed (see Configuration below), then run /leather reload.
leather-auth-bridge.jar Latest stable release · Compatible with Paper 1.19–1.21
Download Plugin

Auth Bridge Plugin

The auth bridge plugin handles the handshake between your server and a connecting Leather Client player. When a player joins, the plugin reads their Leather session token and authenticates them silently — no /login command, no password screen.

Players not using Leather Client are unaffected and go through your server's normal auth flow.

Configuration

The config file lives at /plugins/LeatherAuth/config.yml and is generated on first run.

# LeatherAuth config.yml

# Secret shared between the server and Leather Client
# Change this to any long random string
secret: CHANGE_THIS_TO_A_LONG_RANDOM_STRING

# Allow players not on Leather Client to join
allow-vanilla: true

# Kick message for failed auth
kick-message: "Authentication failed. Please use Leather Client."
Important: Change the secret value. Anyone who knows this string can spoof auth tokens. Use a long, random string (32+ characters).

Offline Mode

If your server is configured for local network play (online-mode=false in server.properties), the auth bridge handles player identity using Leather's internal session system instead of standard authentication servers.

To enable offline support, set the following in your config:

offline-mode: true
Offline mode is designed for private or LAN servers. Enabling it removes standard account verification, so only use it in trusted network environments.

Commands

  • /leather reload — Reload the plugin config without restarting
  • /leather status — Show active authenticated sessions
  • /leather revoke <player> — Revoke a player's session token

All commands require the leather.admin permission node.

Troubleshooting

Players are getting kicked on join

Check that the secret in your server config matches what's configured in the player's Leather Client. Mismatched secrets will cause auth failures.

Plugin doesn't load

Make sure you're running Paper or Spigot. Vanilla and Fabric servers are not supported by the auth bridge.

Auto-login isn't working

Confirm the player is running Leather Client (not vanilla) and that the plugin version matches the client version.