React is the most popular frontend library. It uses a component-based architecture and virtual DOM to build fast, interactive user interfaces.
React dominates frontend development. Its component model — where UI is broken into reusable, composable pieces — has become the standard way to think about building interfaces. React's virtual DOM efficiently updates only what changes, and its hooks API provides a clean way to manage state and side effects. The ecosystem is enormous: React Router for navigation, Redux and Zustand for state management, React Query for server state, and thousands of component libraries. React also powers React Native for mobile development and is the foundation for meta-frameworks like Next.js and Remix.