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.
PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others.
France
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Visual Paradigm for UML (VP-UML) is a UML design tool and UML CASE tool designed to aid software development. VP-UML supports key modeling standards such as Unified Modeling Language (UML) 2.4, SysML, ERD, DFD, BPMN 2.0, ArchiMate 2.0, etc.
Hong Kong SAR China
StarUML is a program to develop fast, flexible, extensible, featureful, and freely-available UML/MDA platform running on Win32 platform. The goal of the StarUML project is to build a software modeling tool and also platform that is a compelling replacement of commercial UML...
South Korea
Modelio is an open source modeling tool supporting natively UML, BPMN and model exchange with XMI. It allows to draw all UML2 diagrams and specific diagrams for business process modeling. It is easy and powerful with the capacity to add new functionalities to the application.
FranceEU
UMLet is an open-source UML tool with a simple user interface: draw UML diagrams fast, export diagrams to eps, pdf, jpg, svg, and clipboard, share diagrams using Eclipse, and create new, custom UML elements.
Astah UML is a UML modeling editor with a user-friendly interface. It allows for the creation of various UML 2.x diagrams and mindmaps. The software includes features such as auto-creation of class diagrams, customizable shortcut keys, and merging project files.
Japan
Graphical modelling open source UML2 tool based on Eclipse environment.
United States
Lightweight, powerful, easy to use, UML tool
Software Ideas Modeler is a lightweight and powerful CASE tool. It supports UML 2.2 diagrams and a lot of other ones. Software Ideas Modeler is freeware (for non-commercial use). Commercial user may use this software only after buying.
SlovakiaEU
The PlantText tool is an online tool for quickly creating UML (Unified Modeling Language) diagrams. Unlike most tools, PlantText can build diagrams without the use of a mouse because it is based on PlantUML markup language.
NClass is a free tool to easily create UML class diagrams with full C# and Java language support. The user interface is designed to be simple and user-friendly for easy and fast development. Properties, enums, delegates and other language specific elements are fully supported...
HungaryEU
Violet is a UML editor with these benefits: Very easy to learn and use. Draws nice-looking diagrams. Completely free. Cross-platform. Violet is intended for developers, students, teachers, and authors who need to produce simple UML diagrams quickly.
United States
WhiteStarUML is a fork of StarUML with an intent to revive its Delphi code base by updating code to recent Delphi editions, reducing dependence on third party components and fixing bugs and adding new features.
PolandEU
