Luanti

Luanti, originally known as Minetest, is a free, open-source voxel game engine and platform designed to let players, modders, and developers build and play diverse sandbox-style 3D worlds. Written in C++ for core performance and Lua for scripting, Luanti runs on multiple operating systems (Windows, macOS, Linux, BSD variants and even Android), making it highly accessible and cross-platform. Rather than being a single game, Luanti is meant as an engine and toolkit: individual “games” are actually collections of mods — written in Lua — that define terrain, items, NPCs, mechanics, and rules. This modular design enables rich customization and community-driven content: users can install new games, mods, and texture packs via a built-in content browser that draws from a central repository (ContentDB). Luanti supports both single-player and multiplayer via servers; players can host their own or join publicly listed ones, with server-side mods being applied automatically.