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

Whiteboard is an open-source desktop application designed for collaborative software design. It allows humans and AI agents to work together on the same workspace, drawing on an in-app canvas to describe their work. Whiteboard can be integrated with existing tools like Claude Code, Codex, and others, providing an SDK for the agent to interact with the canvas.

The platform works best with models such as GPT-6, Luna, and Claude Opus 5.5 due to their intelligence, cost-effectiveness, and speed. Users can create prompts to effectively utilize Whiteboard, and the system's configuration defaults are open-source.

Whiteboard provides a unique feature where users can click on visualizations such as sequence diagrams or entity relationship diagrams and jump directly to the underlying code. When navigating the codebase, users gain access to VSCode keybindings and Language Server Protocol (LSP) support out of the box. To address raw diff views' noise, a semantic, AST-aware diff viewer has been developed in Rust, allowing users to focus on relevant code changes.

The platform emphasizes transparency and traceability, enabling agents to query and link their own traces on Whiteboard. This visualization helps users understand the decisions made during the implementation process and how requirements were translated into code. Whiteboard operates on MIT-licensed code and can run against local checkouts of repositories. Although users cannot edit files within Whiteboard, they can contribute to the project via pull requests while adhering to the established Code of Conduct.

Whiteboard does not collect sensitive information such as your code, diffs, or prompts, ensuring user privacy. Users can turn off telemetry if desired. The application is available under the MIT License, and its source code is available for review. Developers are encouraged to file issues for additional features like file editing support or to address any concerns. For further assistance, users can join the Whiteboard Discord community.