When I wrote C4 Context Diagrams in GitHub READMEs to show how to use GitHub’s support for Mermaid diagrams, I was disappointed with the output. One of the nice things about the Diagrams-as-Code movement was that the default layout should be good enough. I found that even simple diagrams looked bad by default, and I had to spend too much time to make them look good. To be fair, I think C4 support is still in beta.

I’m mostly interested in C4 diagrams in my documents, and for that, Mermaid supports PlantUML syntax. I wanted to try PlantUML, but I assumed that the rendering would be similar to Mermaid. I was wrong.

My documentation is in GitHub for open-source projects, but for private projects, I use Confluence. I found the PlantUML for Confluence plugin from Stratus and ported one of my system context diagrams. It took a few minutes and 13 lines of code—one for each component and one for each relationship. The default layout was fine.

The rest of my diagrams are more complex. I’ll be porting them over the next few days.