libGDX is a cross-platform Java game development framework based on OpenGL (ES) that works on Windows, Linux, Mac OS X, Android, iOS and your WebGL enabled browser. It provides a well-tried and robust environment for rapid prototyping and fast iterations. LibGDX does not force a specific design or coding style on you, it rather gives you the freedom to create a game the way you like it.
libGDX is licensed under Apache 2.0 meaning you can use it free of charge, without strings attached in commercial and non-commercial projects. We, however, love to get (non-mandatory) credit in case you release a game or app using libGDX! See our showcase for a selection of some popular libGDX games. libGDX comes with batteries included and provides everything required to develop multi-platform 2D and 3D games with Java.
libGDX also offers a very extensive third-party ecosystem. There are numerous tools and libraries that take a lot of work off the hands of developers. Take a look at awesome-libgdx for a curated list of libGDX-centered libraries and a good starting point for anyone new in the libGDX world.
As we switched to Gradle, there's no need to download libGDX itself anymore: this can all be done by your favorite build tool. We also offer a setup tool, which automatically creates a project for you and downloads everything necessary. See our website for instructions on how to get started with this or read our wiki.
We also provide javadocs online. The javadocs are also bundled as source Jars with every libGDX distribution for consumption in your favorite IDE.
libGDX has a strong developer community constantly improving the code base. We love to get any and all help we can. Our Contributing Guidelines describe the process of helping libGDX to become even better. To contribute, you need to work with libGDX' sources directly, something normal users do not have to go through. The Working with the Source article will give you some directions.
You can also contribute financially to our infrastructure (build server, web server, test devices) via our Patreon!
libGDX is supported by helpful 3rd parties via code contributions, free licenses, test devices and so forth. Make our supporters happy and visit their sites!