Bukkit is an open-source software that allows users to create and manage their own servers for the popular game Minecraft. It provides a framework for developers to create plugins, which are additional features or modifications that enhance gameplay and server management. With Bukkit, server administrators can customize their gaming experience by adding new commands, changing game mechanics, and improving performance. This flexibility has made it a popular choice among the Minecraft community, enabling players to enjoy unique and tailored experiences on their servers.