React
By Meta
React is a declarative, component-based JavaScript library created by Meta for building interactive user interfaces, using a virtual DOM to efficiently update the browser DOM as application state changes.
Definition
React is a declarative, component-based JavaScript library created by Meta for building interactive user interfaces, using a virtual DOM to efficiently update the browser DOM as application state changes.
Overview
React was released by Facebook (now Meta) in 2013 to power dynamic UI in products like the News Feed, and it introduced two ideas that reshaped frontend development: JSX, which blends markup and JavaScript in one file, and a component model that lets developers compose complex interfaces from small, reusable pieces. Under the hood, React builds a virtual DOM representation of the UI; when state changes, it compares the new virtual DOM against the previous one and applies only the minimal set of real DOM updates, a process called reconciliation. Since Hooks arrived in React 16.8, developers manage state and side effects with functions like useState and useEffect instead of class components, and newer features such as Server Components and Concurrent rendering (React 18+) allow parts of a page to stream in and render on the server and client together. React itself is only the view layer, so most real applications pair it with a framework like Next.js or Remix for routing and server-side rendering, a state library like Redux for complex shared state, and a styling approach such as Tailwind CSS. Its component model also extends to mobile development through React Native. SkillVeris covers the fundamentals in the React.js course, and the React Hooks Explained post is a good primer on state and effects.
Key Features
- Component-based architecture for building encapsulated, reusable UI pieces
- Virtual DOM diffing (reconciliation) for efficient, minimal DOM updates
- JSX syntax that blends markup and JavaScript logic
- Hooks (useState, useEffect, useContext, and more) for state and lifecycle in function components
- Unidirectional data flow that makes state changes predictable
- React Server Components and Concurrent rendering for streaming and mixed rendering
- Massive ecosystem of routing, state management, and UI libraries
Use Cases
History
React is a JavaScript library for building user interfaces, based on reusable components and a virtual DOM. It was created by Jordan Walke, a software engineer at Facebook, who was inspired by XHP (an HTML component system for PHP). React was first deployed in Facebook's News Feed in 2011 and in Instagram in 2012, then open-sourced at JSConf US in May 2013. Its component model and JSX syntax initially drew skepticism but went on to reshape front-end development, popularizing declarative UI and a component-based architecture. React later introduced Hooks (2019) and a concurrent rendering model, and it remains one of the most widely used front-end libraries in the world, maintained by Meta and a large open-source community.
Sources
- React — official website · as of 2026-07-17
- React on GitHub — facebook/react · as of 2026-07-17
Frequently Asked Questions
From the Blog
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