Visual Paradigm Online is a web-based diagramming software designed for fast creation of technical and business drawing. Its free UML design tool lets you create UML sequence diagram easily through drag-and-drop. The Free Edition is free for non commercial use and supports not only UML sequence diagram but also the other UML diagrams and ERD.
Create as many diagrams as you like. Output diagrams into images (PNG/JPG/GIF/SVG) or PDF. Simply free!
Easy-to-use online sequence diagram tool that features:
A rich set of powerful features are there to support you in drawing awesome sequence diagrams:
Try it yourself. Just browse the Sequence Diagram examples below and click Open Diagram to open and edit. You will see for yourself that it is everything we say it is, or perhaps more.