HMCL

HMCL, short for Hello Minecraft! Launcher, is a desktop application for launching Minecraft. It is written in Java and runs across different operating systems. The launcher is designed for players who want more control over their Minecraft setup than the official Mojang launcher provides.

It supports mod management, letting players install and organize modifications that change or extend the game. It can automatically install widely used modding tools like Forge, LiteLoader, and OptiFine, which are frameworks many Minecraft mods depend on. The launcher also supports creating and sharing modpacks, which are pre-assembled bundles of multiple mods packaged together for easy distribution. Players can customize the look of both the game and the launcher interface.

The launcher handles Minecraft authentication and manages multiple game versions, so players can switch between different Minecraft versions without reinstalling anything. That version management is one of the more practical reasons people use third-party launchers over the default one.

The README is primarily aimed at developers who want to contribute code rather than end users. It describes the code package structure and an API for building plugins that extend the launcher. The plugin system is event-based: third-party code can listen for events such as a game launching, a login completing, or a version loading, and respond to them programmatically. Plugins are loaded from a folder automatically when the launcher starts.

The project is open source under the GPL v3 license.