Second this.

Reference for anyone looking I to it: https://c4model.com/

There is also quite a lot of options for helping create these diagrams. I've found https://structurizr.com/ to be the best of what I've tried so far.

I like the idea behind structurizr, but I found the syntax to be too constraining and the tooling around it to be difficult to deal with. That was 2 years ago though,maybe I should revisit it.

icepanel implements tooling

https://icepanel.io/

Looks really good. Some nice articles in the blog section too.

Not sure it will have changed that much.

There are definitely limitations, for me being able to encode and version control diagrams and system documentation alongside a codebase made the tradeoff worth it.

Third this. Don't look any further, just do it!

Also, PlantUML + C4 is like peanut butter & jelly:

https://github.com/plantuml-stdlib/C4-PlantUML

I'll gladly give up control of layout, and accept some ugliness, to never again have to worry about dragging boxes and arrows to be pixel-aligned, and then do it all over again when I add another box...

It looks like Mermaid has C4 support too:

https://mermaid.js.org/syntax/c4.html

Oh thanks, this looks like the kind of thing I was searching for — will read up on it