A shared whiteboard for pair programming and architecture sketches

Why pair programmers pick cnvs.app

• No screenshare juggling. Both of you see the same canvas, both can edit. Faster handoffs than "stop sharing, you share, I share back".
• Mermaid diagrams from plain text. Sequence diagrams, flowcharts, ER schemas — type, render, edit. The diff is text-based which makes "we changed this part" obvious.
• Markdown text nodes. Drop a function signature with `code blocks` and proper formatting, annotate around it.
• Optional AI third pair via MCP. Connect Claude Code / Claude Desktop / Cline to https://cnvs.app/mcp — your AI can read the board, propose changes by drawing or typing, and you see them live.
• Saves the design context. Print to PDF, link the URL in your PR description, future-you knows why the design was the way it was.

Mermaid sequence diagram example

sequenceDiagram
  participant Client
  participant API
  participant Worker
  participant DB
  Client->>API: POST /upload
  API->>Worker: enqueue(job_id)
  Worker->>DB: write status=processing
  Worker-->>Client: 202 Accepted
  Worker->>DB: write status=done
  Client->>API: GET /status/{job_id}

Drop that text into a cnvs.app text node and Mermaid renders it as a proper sequence diagram. Both pair members see it; either can edit the source.

AI as a third pair via MCP

cnvs.app exposes a Model Context Protocol endpoint. Add it to Claude Desktop or Claude Code once and your AI can read the board with get_board, propose architecture changes by drawing strokes and dropping text nodes, and respond to your edits in real time. The AI's contributions are visually distinguished (purple border) so you can tell what came from where.

→ How to set up the MCP integration

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