SteamCraft - Minecraft P2P Multiplayer over Steam (Spacewar)

SteamCraft is an open-source Minecraft mod that allows you to play multiplayer with your friends using Steam's Peer-to-Peer (P2P) network infrastructure via Spacewar (AppID 480).

Say goodbye to port forwarding headaches, Hamachi/Radmin VPN issues, and waiting in queues on free hosting services!

Key Features

• Zero Port Forwarding: No need to touch your router, open ports, or configure firewalls.
• No Third-Party VPNs: Forget about Hamachi, Radmin VPN, or ngrok.
• Direct and Secure: Traffic is encrypted and tunneled through Valve's Steam Datagram Relay (SDR).
• Full Steam Integration: In-game Steam Friends list and native Steam Overlay (Shift + Tab) invite support.
• Batteries Included: Pre-bundled with native Steamworks libraries (steam_api64.dll, steamworks4j64.dll, Linux .so, and macOS .dylib). No extra installation required!

How to Play

As Host (Opening your world):

1. Make sure the official Steam client is running in the background.
2. Launch Minecraft and load into your Singleplayer world.
3. Press Esc and select "Open to LAN" (or "Abrir en LAN").
4. Configure your desired game settings and click "Start LAN World".
5. The mod will automatically register your session with Steam.
6. Open your pause menu and click "Invite Steam Friends", or open the Steam Overlay (Shift + Tab), right-click any friend, and click "Invite to Game".

As Guest (Joining a friend):

1. Ensure you have Minecraft open on the same game version and modloader as the host.
2. Head to the Multiplayer screen.
3. Click the "Steam Friends" button at the top of the screen.
4. Click "Join" next to your friend's name.
5. Alternative: If your friend sent you a Steam invite, simply accept it directly from your Steam chat notification!

Supported Platforms & Versions

Client (LAN Multiplayer):

• Fabric: 1.16.5, 1.18.2, 1.19.2, 1.19.4, 1.20.1, 1.20.4, 1.21.1, 26.3 (Requires Fabric API)
• Forge: 1.7.10, 1.12.2, 1.16.5, 1.18.2, 1.19.2, 1.19.4, 1.20.1, 1.20.4, 26.3
• NeoForge: 1.20.4, 1.21.1, 26.3

Dedicated Servers (24/7 Hosting):

• Paper / Spigot: Universal plugin (steamcraft-spigot.jar) compatible with 1.12.2 up to 26.3+.
• Fabric / Forge / NeoForge Server: Dedicated server jars auto-detect headless servers and publish the port via Steam.

Installation

1. Download the .jar file corresponding to your mod loader (Fabric, Forge, or NeoForge) and game version.
2. Place the .jar inside your .minecraft/mods folder.
3. Launch Minecraft with Steam open in the background