Text to sequence diagram can also be done by something called PlantUML (locally installed software in Java, which uses Graphviz).<p><a href="https://plantuml.com/sequence-diagram" rel="nofollow">https://plantuml.com/sequence-diagram</a><p>David Moon's implementation of markdown has sequence diagram support (source code in Python, Common Lisp and Lunar):<p><a href="http://users.rcn.com/david-moon/MMD/HTML/directives.html" rel="nofollow">http://users.rcn.com/david-moon/MMD/HTML/directives.html</a>