Slime Login

Slime Login#

Authentication for Minecraft servers and Velocity networks. Premium players are verified by Mojang and logged in automatically; cracked players register with a password. One jar, no dependencies.

Paper 1.20 → 26.2 Velocity BungeeCord Folia ready Java 17+ SQLite included No ProtocolLib

One jar, three roles#

Drop the same slimelogin.jar everywhere. It works out what it is on its own.

🖥 Single server#

Full authentication on one Paper server. Registration, login, sessions, premium auto-login. Set it up →

🔗 Proxy#

Velocity or BungeeCord. Players authenticate once for the whole network, before they reach any backend server. Set it up →

🛡 Bridge#

A Paper server behind a proxy. Holds players still until the proxy says they are through. How it works →

Nothing to choose

Detection is automatic. A Paper server with proxy forwarding enabled becomes a bridge; anything else runs standalone. You can still force it with mode: in config.yml.

What it does#

  • ✅ Premium auto-login

    A player whose name belongs to a paid Minecraft account is verified by Mojang during the handshake and logged in with their real UUID and skin — no command, no password, first join.

    How it works

  • 🔒 Cracked accounts, safely

    Everyone else registers with a password hashed by BCrypt, off the main thread. Brute-force lockout, per-IP account limits and an optional captcha come as standard.

    Protection

  • ⏱ Sessions & trusted IPs

    Returning players skip the password while their session lasts, bound to the IP it was created from so nobody can inherit it by reusing a username.

    Sessions

  • 🗄 Migration built in

    Import accounts straight out of nLogin — BCrypt, SHA and Argon2 passwords all keep working, and are quietly upgraded to this plugin's own hashing on first login.

    Migrating

  • 🧊 Bedrock players

    Players arriving through Geyser and Floodgate join straight into the game. Xbox Live already authenticated them, so no password is asked for.

    Bedrock

  • 🌐 Folia ready

    Regionised servers — Folia, Canvas — are supported by the same jar. Every task is scheduled per region and every teleport is asynchronous.

    Installation

Install in one minute#

  1. Put slimelogin.jar in plugins/.
  2. Set online-mode=false in server.properties.
  3. Start the server, put your key in plugins/slimelogin/config.yml → license-key.
  4. Restart.
  1. Put slimelogin.jar in the proxy's plugins/ and in every backend server's plugins/.
  2. Turn off online mode on the proxy — online-mode = false in velocity.toml, or online_mode: false in BungeeCord's config.yml.
  3. Start the proxy, put your key in plugins/slimelogin/config.yml → license-key.
  4. Restart.

Backend servers need no key and no configuration.

Full installation guide Command reference

Requirements#
Server Paper 1.20.1 → 26.2 (forks included — Purpur, Folia, Canvas), Velocity 3.3 → 4.1, or BungeeCord 1.16 → 26.1
Java 17 or newer
Database SQLite — included in the jar, nothing to install
Dependencies None. No ProtocolLib, no external libraries
License A key from devlio.store, on the proxy or the single server