React.js

React.js is a JavaScript library used to build user interfaces, primarily for websites and web applications. It helps developers create dynamic, interactive pages by breaking the interface into reusable components, which makes updates and maintenance more efficient. React efficiently updates only the necessary parts of a page when data changes, resulting in faster performance and a smoother user experience. It’s widely used because it simplifies complex UI development and integrates well with other tools, making it a popular choice for building modern, scalable web applications.