BOUML vs kUML

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.

kUML is a modeling tool that expresses UML 2.x, SysML 2, C4, BPMN 2.0, and ERM as a type-safe Kotlin DSL. It supports all 14 UML 2.x diagram types, with compile-time validation and IDE support. Built-in transformations generate JPA, OpenAPI 3.0 YAML, Kubernetes manifests, and Dockerfiles. Integrations include CLI, Gradle, IntelliJ, Obsidian, Asciidoctor, and VS Code. For interoperability, it supports Structurizr DSL round-tripping and optional XMI through the kuml-io-emf module. kUML also includes an MCP server for agent introspection and a kuml ai subcommand for AI-assisted modeling. It is free and open source under Apache 2.0, with no paid plans or feature limits stated. It runs on Windows, macOS, Linux, and the web, and can be deployed both self-hosted and through other means. Install options include packages for major desktop systems, Docker, and Maven Central library modules. Rendering Kotlin scripts executes their source code, so use only scripts or workspaces you trust.