BESSER vs JetUML

BESSER is an open-source low-code platform for building smart applications by modeling once and generating APIs, databases, agents, and deployments. Its 15+ generators cover databases, REST APIs, web apps, AI agents, and deployment manifests. Built-in modeling includes class diagrams, state machines, object diagrams, agents, and deployment specifications. The GUI Creator deterministically generates complete React frontends from platform-independent GUI models, and AI-assisted modeling supports software with embedded AI components. BESSER connects through an MCP server to Claude Desktop, Cursor, and other MCP-aware clients; BESSER Skills also integrate with Claude Code, Cursor, and Copilot for model and code-generation workflows. Generated Docker components can be used to deploy a running application from a model. The project is MIT-licensed and free, with no freemium tier or hidden fees. It runs on the web, Linux, macOS, and Windows. The Python package installs with pip, and the full codebase can run locally for extensions and generators. It is tested on Python 3.10, 3.11, and 3.12; Python 3.13 is not supported yet. Support includes an on-page assistant, email, and weekly GitHub bug triage.

JetUML is a free desktop editor for sketching software designs with UML. It supports class, sequence, state, object, and use case diagrams, keeping its feature set focused on core diagramming. Association edges are laid out automatically, and moving nodes changes their paths. A validity check reports diagram problems through temporary notifications. You can export diagrams as SVG, PNG, or JPEG images, or copy them to the system clipboard for use elsewhere. JetUML saves diagrams as JSON in a documented open format with a schema for each diagram type. It runs on Windows, macOS, and Linux. Distribution uses Java archives, including an operating-system-independent archive that requires Java and JavaFX; a community Nix package is available for macOS and Linux. The application is licensed under GNU GPL version 3 or later. JetUML states that it collects no information and accesses the network only to open Help-menu web pages. Larger diagrams can reduce performance.