I love Excalidraw, I use it all the time for work to quickly draw up a proposal for a customer. But its annoying I have to re-draw the same thing, but better in Draw.io / Visio when it comes to writing the formal documentation later.

Vellum is designed to give you the speed of a whiteboard, but the architecture-diagram-finish in quality.

It uses YAML to store everything, and even has a 'graph' section for those of you who like the diagram-as-code elements of mermaid... but vellum allows full authoring of layout without the restrictions of Mermaid.

I love it to bits. I hope you will too.

Been working on it a while, but decided to make it source available here: https://github.com/blueprintr-io/vellum-editor

Proud to say its not purely vibe coded slop, but I used Claude to help with some of the more challenging geometry based elements and some housekeeping stuff.