React is a free and open-source JavaScript library for building user interfaces, maintained by Meta and a community of developers. Released in 2013, React introduced the world to declarative components, the virtual DOM, and unidirectional data flow.
React 18+ ships Concurrent Rendering, automatic batching, Suspense for data fetching, and Server Components — enabling a new generation of fast, streaming-rendered applications via frameworks like Next.js and Remix.
JavaScript library for building user interfaces. Component model that defined a decade of frontend.
✨ Features
UIs as composable functions. Props in, JSX out. Trivial to reason about, trivial to test.
useState, useEffect, useMemo, useReducer. Stateful logic shared between components without classes.
Render in chunks. Interrupt low-priority work, prioritize user input. Suspense for async data.
Render on the server, stream HTML, hydrate selectively. Zero client JS for static content.
Best-in-class browser extension. Inspect tree, profile renders, time-travel through state.
