Luanti is a free open-source voxel game engine with easy modding and game creation. This is a custom build of Luanti 5.15 with VoxeLibre 0.91.2, but more games will be added soon!

kaesual.com gives you a virtual IPv6 address to play peer to peer with other players - no game server required. This is not your real IP address, and it will only work in this Luanti version.

If you create a world, just enable "Host server" and share your virtual IPv6 address with your friends. They can then join by entering your virtual IPv6 address in the "Join game" menu. You can also join other players' worlds.

Saved worlds are stored in your browser's file system and listed in the Right Side Panel. They normally persist across browser restarts, but I recommend downloading them after you're done playing. In case your browser cache is cleared, you can always upload them again.

My Luanti version is open source - you can find the source code on GitHub: https://github.com/kaesual/luanti/tree/web
Have fun!

Tip: There is a VoxeLibre server running on kaesual.com, you can find it in the "Join game" menu.