D2 has been around for a while (and has been posted here before) but still surprisingly unknown. It's so much better than mermaid – giving them a boost with this post!

D2 has a lot of merits but there’s little that sells it over PlantUML or Mermaid - I do feel like diagrams-as-code is still waiting for a killer program that makes everything else obsolete.

I’m forever chasing that dragon. In the meantime I still recommend D2 if PUML is feeling a bit stale.

I chose D2 as for our AI's "generate diagram" tool in https://zo.computer and it works quite well. I think the fact that D2 is more expressive than Mermaid is a useful property when doing AI-aided diagram generation.

Recent post on D2 (73 comments):

[1] D2 (text to diagram tool) now supports ASCII renders:

https://news.ycombinator.com/item?id=44954524

I have been looking at things like D2 and Penrose, trying to wrap Python around them to make it a bit easier to script up diagrams based on data.

Working through the problem I realize I probably would have a better time with something like Haskell but I do think the lower the barrier to entry is for drawing up stuff with these tools the more people will reach for programmatic diagramming to help debug and explain things.

The biggest problem with most of the declarative tools like D2,dot,mermaid etc is that they tend to not really offer "declare, then tweak" workflows. You can of course generate some SVG and then tweak it in Inkscape, but sometimes you just want to move something a bit after layout, constraints be damned.

Penrose makes that easier, at the cost of ... I guess everything else being weirder and randomized.