M3E Canvas

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.

A downloadable web-development project bundle from GreatStack for building a full-stack AI website builder with MongoDB, Express.js, React.js, and Node.js. The project includes starter assets and source files for a React website generator that accepts text prompts, builds websites step by step, exposes generation progress, and supports manual source-code editing, follow-up AI prompts, exporting, and publishing. Its tutorial project includes user authentication, REST APIs, an OpenRouter model integration, and an agent chat API for updating generated projects.

Doop is an open-source multiplayer design canvas where people and AI agents create and edit designs together. Each canvas contains frames that render real HTML in sandboxed iframes; humans edit in the browser, while agents connect through the built-in Model Context Protocol (MCP) server and can create frames, stream HTML in chunks, inspect screenshots, and revise designs. The app synchronizes cursors, presence, frame edits, agent status, comments, tasks, and activity over WebSocket rooms, and includes a server-side Doop Agent that can process queued cards, mentions, and feedback through specialist roles. Canvases are private by default, with email invitations or optional link sharing, and agents inherit the access of the user who authenticates them. Doop also provides design-memory features for exemplar frames, decisions, and proposed style rules, and can be self-hosted with Docker Compose or Bun using embedded Postgres through PGlite.

Excalidraw is an open-source virtual whiteboard for creating hand-drawn-style diagrams, wireframes, and other canvas-based drawings. It provides tools for shapes, arrows, lines, freehand drawing, image insertion, labeled and bound arrows, zooming, panning, undo and redo, dark mode, shape libraries, localization, and export to PNG, SVG, clipboard, or its open JSON format. The editor is available as an npm package for integration into applications. The hosted Excalidraw.com app adds real-time collaboration, end-to-end encryption, browser autosave with local-first behavior, offline PWA support, and shareable read-only links. The videos describe using Excalidraw to visualize Mermaid-generated diagrams and to manually map multi-step AI workflows with jobs, arrows, parallel lanes, checks, and human approvals.