Overview
SimpleLogin provides a seamless hybrid authentication system that automatically detects premium (official Mojang) accounts while requiring cracked/offline players to register with a password. One single JAR works across both Paper and Velocity — no separate downloads needed.

Key Features

• Automatic Premium Detection — Official Mojang accounts are recognized automatically via Mojang API and logged in instantly. No /register or /login required.
• Cracked Account Protection — Offline players must register with a secure BCrypt-hashed password. Sessions are validated by UUID + IP to prevent impersonation.
• Universal JAR — Deploy the same file on both Paper (backend) and Velocity (proxy). Automatic platform detection.
• Velocity Limbo Support — Full LimboAPI integration keeps unauthenticated players in a secure limbo state with /login and /register commands.
• Multi-Database Support — SQLite (zero config, file-based) and MySQL/MariaDB (cross-server sync) with HikariCP connection pooling.
• Database Auto-Backup — /sl backup, /sl backup list, /sl backup restore with tab completion for .db/.sql files.
• Auto-Install LimboAPI — Detects missing LimboAPI on startup and downloads the latest compatible version automatically.
• Full i18n — All player-facing messages are configurable per-language (English/Spanish included). Console logs in English.
• Anti-Bot Protection — Per-IP connection rate limiting, max accounts per IP, IP binding, and login attempt cooldowns.
• Advanced Session Validation — UUID-based session checks prevent cracked players from stealing premium sessions. Supports deferred session handling for race-condition-free authentication.
• Admin Commands — /sl unregister, /sl forcepremium, /sl setspawn, /sl resetip, /sl setip, /sl status, /sl resetpassword, /sl info, /sl reload, /sl backup

How It Works

1. Player connects to Velocity proxy
2. SimpleLogin queries Mojang API to detect if the account is premium
3. Premium accounts are forced into online-mode with their real Mojang UUID
4. Cracked accounts enter limbo and must /register then /login
5. Sessions persist for 24 hours (configurable) with UUID-based validation
6. Reconnections are automatically authenticated if session is still valid

Installation

1. Drop SimpleLogin.jar into your Velocity plugins/ folder
2. Drop the same JAR into your Paper backend plugins/ folder
3. Start both servers — config.yml is generated automatically
4. (Optional) LimboAPI will be auto-downloaded on first startup
5. Configure database, language, and other settings in config.yml
6. Run /velocity reload or restart

Commands

Command	Description	Permission
/register <pass> <confirm>	Create a cracked account	simplelogin.register
/login <pass>	Authenticate with password	simplelogin.login
/premium [confirm]	Enable premium auto-login	simplelogin.premium
/sl	Admin help menu	simplelogin.admin
/sl unregister <player>	Reset a player's account	simplelogin.admin
/sl forcepremium <player>	Toggle premium mode	simplelogin.admin
/sl setspawn <main|auth>	Set spawn locations	simplelogin.admin
/sl resetip <player>	Release bound IP	simplelogin.admin
/sl setip <player>	Update bound IP	simplelogin.admin
/sl status <player>	Show account status	simplelogin.admin
/sl resetpassword <player>	Generate temp password	simplelogin.admin
/sl backup	Create database backup	simplelogin.admin
/sl backup list	List available backups	simplelogin.admin
/sl backup restore <file>	Restore from backup	simplelogin.admin
/sl info	Show plugin diagnostics	simplelogin.admin
/sl reload	Reload configuration	simplelogin.admin
/changepassword <old> <new>	Change your password	(all players)
/logout	End your session	(all players)

Permissions

Permission	Default	Description
simplelogin.admin	OP	Access to all /sl admin commands
simplelogin.premium	true	Use /premium command
simplelogin.register	true	Use /register command
simplelogin.login	true	Use /login command

Configuration
All settings are in plugins/simplelogin/config.yml:

• database — SQLite, MySQL, or MariaDB with connection pooling
• servers — Main and auth server names for spawn routing
• auth — Password length, session duration, login limits, max accounts per IP
• security — IP binding, anti-bot rate limiting
• limbo — Enable/disable limbo mode
• language — en or es (custom messages in messages/ folder)

Requirements

• Java 17 or higher
• Paper 1.20.4+ (backend)
• Velocity 3.3.0+ (proxy)
• LimboAPI (optional, auto-downloaded)