Storybook is an open-source tool for developing UI components in isolation for React, Vue, Angular, and more. It's a playground for UI components, allowing developers to design, build, and organize UI components outside their applications. Storybook supports HTML, React, React Native, Vue.js, Angular, Svelte, and many other frameworks. Storybook helps to encourage the development of components in isolation, which can improve component reuse, testability, and development speed. It is often used with other tools and technologies, including various testing frameworks and documentation tools. Developers can also interactively develop and test UI components without running the entire application, making it a very efficient tool. It also allows developers to create a component library or style guide and document their components with markdown, making sharing details with the rest of their team easier.