Cosmic IDE is described as 'There are a lot of cases where you want to quickly test some Java code but don't have your computer open besides you. You open your browser and search for some website for this purpose. But you're neither guaranteed to have internet all the time (do you?' and is a IDE in the development category. There are more than 50 alternatives to Cosmic IDE for a variety of platforms, including Windows, Mac, Linux, Web-based and Android apps. The best Cosmic IDE alternative is VSCodium, which is both free and Open Source. Other great apps like Cosmic IDE are Microsoft Visual Studio, Zed Editor, Eclipse and Apache NetBeans.