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Z-Auth Backend addon

Z-Auth Backend addon

Auth Backend is the lightweight backend guard for ZCraft Auth. It runs on Spigot, Paper, Purpur, and Folia servers, protecting players until the proxy confirms they are logged in.

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Compatibility

Minecraft: Java Edition

1.21.x

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Published 2 days ago

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Auth Backend

Auth Backend is the lightweight backend protection layer for ZCraft Auth.

It runs on Spigot, Paper, Purpur, and Folia backend servers, keeping players restricted until the proxy confirms they are logged in.

The proxy handles accounts, passwords, sessions, 2FA, and database storage.
The backend plugin only protects gameplay until authentication is complete.

Summary

Lightweight backend protection for ZCraft Auth. Runs on Spigot, Paper, Purpur, and Folia servers, blocking gameplay until the proxy confirms the player is logged in. No backend database setup required.

Features

Feature Status
Spigot backend support Yes
Paper backend support Yes
Purpur backend support Yes
Folia backend support Yes
Proxy auth-state sync Yes
Movement protection Yes
Chat protection Yes
Command protection Yes
Inventory click protection Yes
Item drop protection Yes
Item pickup protection Yes
Damage protection Yes
Attack protection Yes
Backend database setup Not required
Backend password hashing Not used
bStats support Yes

What This Plugin Is

Auth Backend is made for Minecraft networks using Auth Proxy on Velocity or BungeeCord.

When a player joins a backend server, Auth Backend checks with the proxy to see if that player is authenticated.

If the player is logged in, they can play normally.
If not, the backend keeps them locked down until login, registration, or 2FA verification is complete.

This keeps backend servers protected without requiring every server to connect to your database.

Downloads

Install the backend jar that matches your server type.

Jar Install on
Auth-Backend-SpigotLegacy-<version>.jar Spigot-style 1.16-1.19 backends
Auth-Backend-Spigot-<version>.jar Spigot-style 1.20-1.21 backends
Auth-Backend-Paper-<version>.jar Paper/Purpur 1.21+ backends
Auth-Backend-Folia-<version>.jar Folia 1.21+ backends

Do not install backend jars on the proxy.
Do not install the proxy jar on backend servers.

Required Proxy Plugin

Auth Backend is not a standalone login plugin.

You must also install the proxy jar:

Auth-Proxy-<version>.jar

on your Velocity or BungeeCord proxy.

The proxy plugin handles:

  • /login
  • /register
  • /logout
  • /changepass
  • /2fa
  • sessions
  • passwords
  • database storage
  • authentication state

The backend plugin only listens for that state and protects the server until the player is logged in.

How It Works

  1. A player joins through the proxy.
  2. The player logs in, registers, or verifies 2FA.
  3. The player connects to a backend server.
  4. Auth Backend asks the proxy for the player's login state.
  5. The proxy replies with the current auth state.
  6. The backend allows or blocks gameplay based on that state.

Backend and proxy communication uses:

zcraftauth:state

No backend database credentials, ports, tokens, or separate linking setup are required.

Backend Protection

Auth Backend can block unauthenticated players from:

  • moving
  • chatting
  • running blocked commands
  • clicking inventory items
  • dropping items
  • picking up items
  • taking damage
  • attacking entities

You can still allow authentication-related commands before login.

Default backend config:

block-movement: true
allow-chat: false
enable-bypass-permission: false

allowed-commands:
  - "/login"
  - "/register"
  - "/l"
  - "/reg"
  - "/2fa"
  - "/totp"
  - "/authenticator"

Operators are not bypassed by default.

To allow bypassing, you must enable it manually and give the player:

zcraftauth.backend.bypass

Performance

Auth Backend is intentionally small and low-impact.

It does not:

  • connect to a database
  • hash passwords
  • perform account lookups
  • manage sessions
  • run the full authentication system

It only listens for protection events and proxy authentication state.

This keeps backend TPS/MSPT impact minimal while still preventing unauthenticated players from interacting with the server.

Requirements

Component Supported
Java 21+
Proxy Velocity or BungeeCord with Auth Proxy
Backend Spigot-style, Paper, Purpur, Folia
Minecraft 1.16-1.19, 1.20-1.21, and 1.21+ backend families

Installation

  1. Install Auth-Proxy-<version>.jar on your Velocity or BungeeCord proxy.
  2. Install the matching Auth-Backend-<version>.jar on each backend server.
  3. Start the proxy and backend servers once.
  4. Configure the proxy plugin.
  5. Restart the proxy and backend servers.
  6. Join through the proxy and authenticate.

Register:

/register <password> <password>

Login:

/login <password>

Important Notes

  • Backend servers do not need database settings.
  • Backend jars do not replace the proxy jar.
  • The proxy jar does not replace backend jars.
  • Install Auth Backend on every backend server that should be protected.
  • Use the backend jar that matches your server software.
  • Authentication logic is handled by the proxy, not the backend.

Support

If something does not work, include:

  • Proxy type and version
  • Backend server type and version
  • Auth proxy jar name
  • Auth backend jar name
  • Console error logs
  • Backend config