OpenPencil

OpenPencil is an open-source design editor. It allows users to create, modify, and manage design documents using a desktop application or a browser-based PWA. The software specifically supports reading and writing .fig and .pen files, enabling users to move design assets between different platforms without losing native data.

The software functions as both a visual editor and a programmable toolkit. It is deployed as a lightweight desktop app built with Tauri for macOS, Windows, and Linux, but it also provides a headless CLI for automating design tasks. This allows users to perform operations like inspecting node trees or exporting assets without ever opening the graphical interface.

Key features

• Native support for opening and saving .fig and .pen design files
• P2P real-time collaboration via WebRTC without accounts or servers
• AI chat integration for creating and modifying nodes via external API keys
• Headless CLI for XPath queries, linting, and design token extraction
• Design-to-code export for JSX and Tailwind CSS
• Auto layout and CSS Grid implementation via Yoga WASM
• Component and variant management with local asset instances
• Vue SDK for embedding the editor into other applications
• MCP server for integration with AI agents like Claude Code and Cursor

The architecture emphasizes programmability and extensibility. It provides a plugin API via an eval command and a headless Vue SDK for developers building custom editing surfaces. The tool includes a comprehensive set of analysis commands to audit design systems, allowing users to find inconsistencies in colors, typography, and spacing. It integrates with multiple AI providers including OpenRouter, Anthropic, and OpenAI, and supports an MCP server that allows external coding agents to inspect or modify design documents headlessly. Users can also convert HTML and CSS directly into editable layers within the editor.

OpenPencil is a flexible, account-free design tool for developers and designers who require a programmable workflow and local control over their design files.