Apps similar to StarUML include yEd Graph Editor, which is free. Other options are Microsoft Visio, Lucidchart, PlantUML and Mermaid. UML Modeling Tools like StarUML are a crowded field, with more than 50 alternatives for Windows, Linux, Mac, the web and Android.
TopCoder UML 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.
United States
the Chronos Web Modeller is a collaborative tool for the creation of UML models with reporting, code and document generator .
A simple JavaScript library to turn text into vector UML sequence diagrams. Heavily inspired by websequencediagrams.com, who offer a server-side solution. js-sequence-diagrams uses Jison to parse the text, and Snap.svg to draw the image.
United Kingdom
ClassBuilder is freeware CASE tool targeted at the C++ developer, running on Win2K-XP. It lets you create, manipulate and navigate classes, class relations, class members and class methods at a high level of abstraction through a graphical user interface.
ckwnc is a uml sequence diagram creation tool that uses an intuitive c-style language to automatically create uml diagrams that can be saved as an image or embedded directly into other pages
While coding with AI assist, I noticed bigger projects need something more rigid as context so the AI coder doesn't stray away when I try to add new features. You know, to keeps its memory fresh and not change the stuff that already works.
Finland
EU
Inwardis keeps what you know about a system as a hierarchical model rather than separate diagrams. Every element can contain sub-elements, so a person or an AI agent opens one level, sees what matters there and drills into a single branch.
EstoniaEU
All-in-one modeling tool for UML, ERD, DFD and flowcharts, with built-in AI features (AI Chat Copilot, AI Code Reverse and an MCP server).
Japan
MockupTiger is a web based application that helps you to build fluid wireframes, mockups or prototypes for your next web application or desktop software.
United States
