Excalihub, an open-source Chrome extension released on March 14, 2026, adds AI diagram generation and several additional features to Excalidraw, the widely used open-source virtual whiteboard. Built by Aykut Sarac — the developer behind the commercial JSON Crack visualization tool — Excalihub integrates with the Anthropic API to let users describe diagrams in plain text and receive fully rendered Excalidraw scenes complete with shapes, arrows, and labels. A companion "Extend Canvas" feature lets the AI read an existing drawing and add to it contextually, so users can build out diagrams incrementally through natural language prompts.
The extension follows a <a href="/news/2026-03-14-tome-open-source-documentation-platform-with-embedded-ai-chat-and-mcp-server">bring-your-own-key model</a>: users supply their own Anthropic API key, stored locally in the browser. No data transits through the developer's servers, a clean privacy model for enterprise and privacy-conscious users. Beyond AI generation, Excalihub adds file save and folder organization, bulk ZIP export, shareable link generation, and a presentation mode that converts Excalidraw frames into keyboard-navigable slides with fullscreen and theme support — features that address longstanding gaps in Excalidraw's native toolset.
Sarac operates under the ToDiagram brand, which encompasses both Excalihub and the freemium JSON Crack SaaS product. Excalihub is MIT licensed and the GitHub repository contains no cross-promotional references to Sarac's commercial offerings, suggesting the project functions primarily as a developer credibility play rather than a direct acquisition funnel. The extension surfaced as a Show HN post and is available on the Chrome Web Store; it can also be built manually from source.