Seems possibly useful, except it's extremely limited.

For example, how do you control positioning? For example in the Graphs option, say I have a Central entry that requires 4 exits to Up, Down, Left and Right. there doesn't seem to be a way to handle that as it quite arbitrary allocates position, I think, alphabetically.

I got curious and found https://asciidoctor.org/docs/asciidoctor-diagram/ is available. Important if you're not wanted to "delegate" this to a web-service.

Wow, looks useful online extension of Graphviz.. Thanks for sharing :)

I think plantuml is a better option, thanks for sharing :)