BOUML vs Gaphor

BOUML is a free UML 2 toolbox for modeling systems and generating code, available as desktop software for Linux, macOS, and Windows. It supports use case, sequence, communication, class, composite class, activity, state, object, composite object, component, and deployment diagrams. Built-in generators cover C++, C, Java, PHP, Python, IDL, and MySQL; reverse-engineering tools are listed for C++, Java, PHP, and MySQL, and round-trip tools for C++, Java, and PHP. Plug-outs provide XMI 1.2 and 2.1 generation, XMI 2.1 import, and Rational Rose model import. External plug-outs can be written in C++ or Java and run separately from BOUML. An HTML documentation generator can output diagrams as PNG or SVG. Project control and synchronization tools support work by several people. The maker says it can handle several thousand classes while using little memory. Version 7.11 is identified as the final release, with patch 4 listed for some distributions. Releases since version 7.0 are free to use; the maker states they come without warranty.

Gaphor is a desktop modeling application for visualizing and documenting applications and systems with UML, SysML, RAAML, and C4. It implements a UML 2 data model and the UML, SysML, and RAAML OMG standards, and supports the C4 model. Its diagram options include Class, Interaction, State Machine, Block Definition, and Requirements diagrams, with diagram items that can be mixed and styled through a built-in engine. Diagrams export to SVG, PNG, PDF, or EPS, including batch export for every diagram in a model. Gaphor can also create a static, interactive, read-only HTML model report that needs no server or backend. As a Python library, it can inspect, generate, or update models through scripts or Jupyter notebooks; a Sphinx extension embeds diagrams in reStructuredText or Markdown documentation. The software is free under the Apache 2 license for Windows, macOS, and Linux. Windows users have installer, portable, and Winget options; macOS requires version 10.15 or newer.