VellumFlow — from whiteboard sketch to polished architecture diagram

Draw at Excalidraw speed, export Draw.io-quality architecture diagrams

Problem

Developers love Excalidraw for quickly sketching proposals, but when writing formal docs they have to redraw everything in Draw.io or Visio. This duplication is annoying, and hand-drawn sketches can't be turned into client-ready deliverables without manual rework.

Solution

A YAML-driven diagram editor: sketch layout at whiteboard speed, then auto-apply alignment, spacing, and styling rules to produce a formal architecture diagram. Includes a C4 model component library, exports to Draw.io/Visio/SVG, and keeps the YAML source under version control.

Users

Architects, solutions engineers, developers writing formal design docs

MVP

A YAML format defining nodes and connections; whiteboard-style sketch mode; one-click formal styling and SVG/PNG export; built-in C4 model components; import Excalidraw sketches as underlays

Revenue

One-time desktop purchase ($29–$59) or annual subscription; team version adds shared component libraries

Why now

Excalidraw proved huge demand for quick sketching, but automated sketch-to-formal-diagram conversion is still missing—and LLM-assisted styling cuts implementation cost