Show HN: Whiteboard (YC W26) – An open-source IDE for thoughtful software design

an open-source IDE for thoughtful software design

Whiteboard is an open-source desktop app where humans and agents can architect software together in a common workspace.

Whiteboard plugs into the tools you already use - e.g. Claude Code, Codex, etc. – and gives your agent an SDK to draw on an in-app canvas to describe its work.

Here’s a 1 min demo video explaining more: https://www.youtube.com/watch?v=ChPn3ftULWE

Download Whiteboard and open the app. Connect Claude Code, Codex, or another coding agent from the welcome screen. Ask your agent to review your current branch against up-to-date main and open the result in Whiteboard. Guidance In our experience, Whiteboard works best with models like GPT-6 Luna and Claude Opus 5.5 for their intelligence, cost, and speed tradeoff.