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Astah ProfessionalPlantUML
Paid

Commercial license with a free trial and student options.

 Free

Free and open source under the GPL.

macOS Windows, macOS, Linux, Web, Command line
  • UML, ERD, DFD and flowcharts in one tool
  • API and free plugins for customisation
  • Covers far more diagram types than most text-based tools
  • Integrations for nearly every editor, wiki and documentation system
  • Paid license after the trial
  • Focused on software modelling rather than general diagramming
  • Requires Java and, for some diagram types, Graphviz
  • The syntax is inconsistent between diagram types
Downloadable app Downloadable app, Web application
Closed source Open source
License not stated License: GPL-3.0
Not stated if an account is needed Not stated if an account is needed
Not stated if it works offline Not stated if it works offline

Checked October 2, 2026

Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.