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