As software developers, all of us used at least one UML design tool such as Rational Rose, Enterprise Architect or even Microsoft VISIO. Those tools have one thing in common - they are commercial and thus cost money… I want to introduce you a nice free sequence diagram editor called SDEdit. It is not a full UML design editor, you can’t draw class diagrams or state diagrams, only sequence diagrams are there.

Markus Strauch, the author of this tool, also called it Quick Sequence Diagram Editor. The UML sequence diagrams are created from a textual syntax and not by drawing objects and lines. There is a text area at the bottom of the window to specify the objects and messages while you can see the sequence diagram itself at the upper part of the window…