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

Hello! We’re Sid, Alex, Ketan, and Milan. We’re building Whiteboard, an open-source desktop app where humans and agents can architect software together in a common workspace. Here’s our repo: https://github.com/devdotfast/whiteboard and our homepage: https://whiteboard.dev.fast/ We were missing the feeling of a “whiteboard session” with another dev where you leave with a deep understanding of a sy

stem, so we built this app for ourselves. 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. We began with an MVP based on HTML artifacts and started rethinking the app as we ran into limitations: 1. Built on top of CodeOSS: We found that in pure HTML tools it was hard to connect a spec or