A free online architecture diagram tool on a real-time whiteboard — no signup. Sketch services, boundaries and data flows freehand, or drop Mermaid diagrams onto the same canvas and share one URL with your team.
https://cnvs.app/mcp so an architecture draft can start from a prompt and finish with humans.| Capability | Heavy diagram suites | cnvs.app architecture board |
|---|---|---|
| Start sketching | New doc, template, often login | Instant board URL |
| Freehand + formal diagrams | Usually one or the other | Both on one canvas |
| Real-time collaboration | Paid seats | Share a URL |
| AI agent read/write | Rare / proprietary | Public MCP endpoint |
| Price | Freemium / enterprise | $0 forever |
Yes. cnvs.app is free with no signup. Open a board, sketch boxes and arrows or drop in Mermaid diagrams, and share the URL — no account, no paywall.
Yes. Share the board URL and every collaborator edits the same live canvas. Changes sync over the real-time channel within seconds.
Yes. Draw boxes and arrows freehand, add sticky notes, and embed Mermaid architecture or flowchart diagrams on the same board.
Yes. Point any MCP client at https://cnvs.app/mcp and the agent can read board state and write text, notes and Mermaid diagrams live beside you.