mage

XMage (Magic: Another Game Engine) is an open-source rules enforcement engine for playing Magic: The Gathering against other human players or computer AI, either on public servers or self-hosted instances. It supports over 32,000 unique cards and more than 91,000 reprints across official sets and custom sets like Star Wars. Key capabilities: - Cross-platform client and server running on Windows, Linux, and macOS - Two-player duels and multiplayer games with up to 10 players, including Commander and other formats - Smart AI opponents for both casual games and draft/deck-building - Cheat-proof design: all rules and hidden information are enforced server-side - Deck editor with import support from multiple apps and services - Player rating system using Glicko - Supports dozens of formats including Commander, Oathbreaker, Cube, Tiny Leaders, Super Standard, and Historic Standard - Single matches and tournaments with elimination or Swiss pairings for up to 16 players - Special test mode for developers to simulate combos and game situations with predefined conditions - ~9,000 unit tests with approximately 80% coverage Users can join public servers such as xmage.today or host their own server, including fully offline local play without an internet connection. A launcher manages client and server installation, requiring Java 8 or later. Community resources include GitHub issues for bug reports and feature requests, a Reddit community, Discord server, and an extensive wiki covering setup, development onboarding, and troubleshooting.