TopCoder UML is described as 'Tool is an easy to use, consistent modeling tool for use in Design and Development competitions. The new tool was built to model sequence, class, use case, and activity diagrams. On top of that, all those elements can have documentation easily attached to them' and is a UML Modeling tool in the development category. There are more than 10 alternatives to TopCoder UML for a variety of platforms, including Windows, Linux, Mac, Web-based and Android apps. The best TopCoder UML alternative is PlantUML, which is both free and Open Source. Other great apps like TopCoder UML are Visual Paradigm, StarUML, Modelio and UMLet.