AI product Open source
PenEcho is an open-source shared canvas for handwriting, equations, diagrams, and spatial context. It reads marks and their spatial relationships on a 20,000 × 20,000 canvas, then places hints, explanations, formulas, plots, diagrams, and other AI-generated drafts beside the original content. Drafts can be moved, resized, copied, accepted, or discarded before becoming part of the canvas ink; users can draw with a stylus or mouse, lasso confirmed ink to move, resize, recolor, or delete it, and send selected content to Typeset without triggering an AI request when editing ordinary ink.
The application supports editable sandboxed HTML widgets, professional diagrams, animations, and live-data plugins, which can be refined in place through incremental unified-diff edits rather than full regeneration. It supports up to ten API or CLI connections, including Kimi, MiniMax, Codex, and Claude Code configurations, with a selectable active connection per client. Canvases can be organized into projects, shared across authorized devices, and exported as cropped PNG files.
PenEcho provides a desktop app and an npm installation requiring Node.js 20.3 or newer. It can run offline with a user's own API or authenticated CLI setup; API credentials remain on the host device and are not sent to browser code. PenEcho Cloud is an optional companion service for private versioned projects, synchronized favorites, linked-device remote access through a relay, and public sharing of Canvases and Widgets as Echoes or Crafts. The project is supported through Moonshot AI's Kimi Open Source Friends program.
2 uses taken from transcripts — each links to the moment in the video.
An open-source shared AI canvas for handwriting, equations, and diagrams. It interprets marks and their spatial relationships, then places movable AI responses beside the original canvas content.
An AI shared canvas that understands written equations, sketches, diagrams, and their spatial relationships. AI results remain movable drafts until accepted, making it useful for preserving visual context.
2 in the library.