StarUML

StarUML is an open-source project to develop a fast, flexible, extensible, featureful, and freely-available UML/MDA platform running on a Win32 platform. UML is continuously expanding standards managed by OMG (Object Management Group). Recently, UML 2.0 is released and StarUML supports UML 2.0 and will support the latest UML standard.

Features and Highlights

UML 2
Compatible with UML 2.x standard metamodel and diagrams: Class, Object, Use Case, Component, Deployment, Composite Structure, Sequence, Communication, Statechart, Activity, and Profile Diagram.

Additional Diagrams
Support to create Entity-Relationship Diagrams (ERD), Data-flow Diagrams (DFD), and Flowchart Diagrams.

Cross-Platform Support
Work with the same UX on multiple platforms including macOS, Windows, and Linux.

Retina Display Support
Supports Retina (High-DPI) Display. All diagrams, texts, and icons are razor sharp and can be exported to High-DPI images (PNG and JPEG).

Extension Manager
Easily discover and install third-party extensions. Many extensions are open source and hosted on Github. Fork one and make your own.

Model-Driven Development
Modeling data are stored in a very simple JSON format, so it can be used easily to generate custom codes by user-defined templates (mdgen).

Fast Modeling
Supports many shorthands in Quick Edit to create elements and relationships at once such as sub-classes, supporting interfaces, etc.

Dark and Light Themes
Support light and dark themes, so you can choose a theme more comfortable.

Auto Update
StarUML checks the latest updates automatically. No more manual download and installation.

Code Engineering
Supports code generation and reverse engineering for major programming languages including Java, C#, and C++ via open-source extensions.

Open APIs
Allows writing your own extensions using HTML5, CSS3, JavaScript, Node.js modules, and APIs for menus, keymaps, dialogs, UIs, metadata, preferences, etc.

Asynchronous Model Validation
Many model validation rules are defined and checked asynchronously whenever you save or open your model files.

Publish HTML Docs
Easy to share models with other analysts, architects, and developers by just publishing HTML Docs.

PDF Export for Clean Printing
Diagrams can be exported to PDF for clean printing with printing options like page layout and sizes.

Markdown Support
Use markdown syntax to edit the element's documentation with the support of syntax highlighting and preview.

Note: You can evaluate for free without a time limit.

Also Available: Download StarUML for Mac