DeepAlts

A Paper plugin for detecting alternate accounts based on IP history, with both shallow and deep scanning modes.

What It Does

DeepAlts helps server staff find potential alternate accounts (alts) by checking which players have logged in from the same IP address, even indirectly through a shared chain of connections.

• /alts <player|UUID> [uuid]: Lists accounts that have used the same last known IP as the target.
• /deepalts <player|UUID> [uuid]: Finds all players connected through any shared IPs across login history using a BFS search.
• /deepaltsconfig <subcommand>: Manage plugin state, cache, and graph configuration.

Add uuid as the second argument to force UUID output instead of usernames.

Features

• Async lookups — won't lag your server
• Caches proxy/host detection results for faster rebuilds
• Excludes proxy and hosting IPs from connection logic
• Supports both player names and UUIDs
• Optional UUID-only output for logging
• Tab completion for player names and admin commands
• Gracefully handles players who have never joined
• Permission-based usage (deepalts.lookup, deepalts.admin)

🔧 Commands

Command	Description
/alts <player or uuid> [uuid]	Shows players with the same last IP
/deepalts <player or uuid> [uuid]	Finds players with any shared IP connections
/deepaltsconfig status	View plugin and cache status
/deepaltsconfig rebuild	Rebuild graph (checks uncached IPs for proxy/hosting)
/deepaltsconfig save	Save all data manually
/deepaltsconfig reload	Reload IP data, graph, and proxy cache from disk
/deepaltsconfig info	Detailed plugin statistics

Permissions

Node	Description
deepalts.*	Grants all DeepAlts permissions
deepalts.lookup	Allows use of /alts and /deepalts
deepalts.admin	Allows use of all /deepaltsconfig admin commands

By default:

• deepalts.lookup and deepalts.admin are granted to server operators (op).

Requirements

• PaperMC 1.20+
• Java 17+

Installation

1. Download the .jar from Modrinth or GitHub.
2. Drop it into your plugins/ folder.
3. Restart or reload your server.