Storybook

Storybook is an open-source "frontend workshop" for building, testing, and documenting UI components and entire pages in isolation from the rest of an application. Teams use it to develop individual components independently of the larger system, review them visually, and test for regressions automatically before integrating them into an app.

The project is maintained by the Storybook community and developed on GitHub under storybookjs/storybook; with more than 84 million monthly installs, over 91,000 GitHub stars, and more than 2,280 contributors, it's one of the most widely used tools in the frontend ecosystem. The current version, v10, supports interaction and visual testing alongside traditional UI development.

With "MCP for React," Storybook introduced Model Context Protocol capabilities that let AI agents connect directly to component libraries — for example, to reuse existing components instead of generating new, inconsistent UI building blocks. Storybook is entirely free to use and runs locally at localhost:6006.