JetUML vs UMLet

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.

UMLet is a free, open-source tool for quickly sketching UML diagrams, including class, use case, sequence, state, deployment, and activity diagrams. Users edit diagram elements by changing text in a small markup dialect rather than configuring pop-up dialogs. UMLet is available as a stand-alone desktop application, an Eclipse plugin, the browser app UMLetino, and a Visual Studio Code extension. The desktop application exports to BMP, EPS, GIF, JPG, PDF, PNG, and SVG, can copy diagrams to the clipboard, and supports command-line batch conversion of UXF files. UMLetino runs in a browser without installation, stores diagrams in browser storage, and exports PNG. Custom elements can be made with Java code that UMLet compiles on the fly, but only in the stand-alone version. The desktop application requires Java and runs on Java platforms such as Windows, Linux, and macOS. UMLet identifies its license as GNU GPL 3.0. It does not generate code from models or reverse-generate models from code; round-trip engineering is not planned.