reladraw

reladraw is a text language for diagrams where you say where things go.

Why not Mermaid or draw.io?

Mermaid, Graphviz and D2 let you declare boxes and connections, then determine positions for you. If you have a particular picture in mind, these aren't the right tool.

On the other hand, tools like draw.io or Excalidraw allow absolute placement, but that means much more effort, whether for humans clicking and dragging nodes around or agents recalculating coordinates and editing verbose XML source code files.

reladraw sits between those two extremes, aiming to have the benefits of a diagram language, like Mermaid, but also having the expressiveness and custom placement that you can get with draw.io. Positions are relative, so you don't have to manually pick coordinates.