Cuberite
A lightweight, fast and extensible game server for Minecraft
...The software recreates core gameplay systems such as world generation, multiplayer networking, and commands while allowing extensive customization through a plugin system. One of its defining features is a Lua-based plugin API that allows developers to easily extend the server with custom features, commands, and gameplay mechanics. Cuberite is designed to run on a wide variety of platforms including Windows, Linux, macOS, Android devices, and embedded systems.