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

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.

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.

icepanel implements tooling

https://icepanel.io/

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

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