What is React?

React is a popular open-source JavaScript library used for building user interfaces, particularly for single-page applications where you want a seamless and dynamic user experience. Developed and maintained by Facebook, React allows developers to create reusable UI components, which makes building complex interfaces more manageable and efficient. At its core, React uses a declarative approach, meaning you describe what the UI should look like for a given state, and React takes care of updating the actual DOM to match that state. This is achieved through a virtual DOM — a lightweight copy of the real DOM — which helps React optimize updates and improve performance. React’s component-based architecture encourages breaking down the UI into small, self-contained pieces, each responsible for rendering a part of the interface and managing its own state. Overall, React is widely adopted because it simplifies the process of building interactive, fast, and maintainable web applications, and it integrates well with other libraries and frameworks in the JavaScript ecosystem.