spool is described as 'Free, open-source, local-first prototyping canvas. Agents author React/TSX frames stored in a project's files. People arrange those frames spatially, compare design directions and walk through interactive flows with working inputs and shared state' and is a Prototyping tool. There are 2 alternatives to spool for a variety of platforms, including Linux, Mac, Windows, Web-based and Cursor apps. The best spool alternative is Pencil.dev, which is free.
Vector UI canvas inside IDEs and desktop apps for creating layouts, using infinite canvas, layers, design system components, Git-compatible .pen files, synced design tokens, and AI-driven UI generation from prompts, aligning code and design efficiently.
United States
Full-featured design workspace merges visuals, agents, and code, enabling live sync of tokens, components, and styles, connects with IDEs, imports databases and content, automates responsive layouts, and streamlines design-to-code with real-time data integration.
United States
