UMLet 15.1

Free UML Tool for Fast UML Diagrams

UMLet is a free, open-source UML tool with a simple user interface: draw UML diagrams fast, create sequence and activity diagrams from plain text, share via exports to eps, pdf, jpg, svg, and clipboard, and develop new, custom UML elements.

Find below the full-featured UMLet as stand-alone app for Windows, macOS, and Linux, or as Eclipse plugin. It is also available as web app called UMLetino, and as extension to Visual Studio Code.       @twumlet

New in 15.1: Relation bug fix ++ log lib update ++ dark mode cleanup..
New in 15.0: Web: zoom, lasso, export, dark mode ++ hi-res export ++ startup..
New in 14.3: Improved OS and Eclipse integration (thx @ruediste) ++ XML security fix..

If you like UMLet, visit us on Facebook, or maybe star it on the VS Code Marketplace or the Eclipse Marketplace! (You can also sponsor UMLet via Github, Patreon, or Paypal. Obliged!)




  • Add elements to a UML diagram with a double click
  • Edit elements using the lower-right text panel
  • Use Ctrl+Space for context-sensitive help
  • Select multiple elements using Ctrl or lasso
  • Press 'C' to copy diagram to the system clipboard
  • Use +/- or Ctrl+mousewheel to zoom
  • Press Shift to avoid sticking relations!


Core Concepts

UMLet is a UML tool aimed at providing a fast way of creating UML sketches. UML elements are modified using text input and a small markdown dialect instead of pop-up dialogs. This core idea is described in a paper.

Learning about the various element features is supported by prototypically using them from sample palettes. Elements can also be modified inside their palettes and immediately used as new templates; this way, users can easily tailor UMLet to their modeling needs.

UMLet also allows users to create their own custom UML elements. An element's look can be modified at run-time by changing a few lines of Java code; UMLet then compiles the new element's code on the fly. Without leaving UMLet, users can thus create and add new element types to their diagrams. These custom elements are outlined here or in this paper.

UMLet supports a variety of UML diagram types: class diagrams, use case diagrams, sequence diagrams, state diagrams, deployment diagrams, activity diagrams -- see some examples.

Finally, porting UMLet to a JavaScript web app, and later to a VS Code extension, is described here. And a brief history in tweets reminisces about the days of old.


You can support this UML tool by linking to this site; by sending us feedback, bug reports, or blurbs we can quote; by giving us a star on the the VS Code Marketplace or the Eclipse Marketplace; by spreading the word on social media; or via Github Sponsors, Patreon, or Paypal. Thank you - any support is truly appreciated!

2001+ :: GNU GPL 3.0