Node is not required in order to use React. You do not need Node to run a React project. React is a client side UI library. What Node offers is a series of tools that allow you to be able to work with React more easily, such as Webpack (gathers code into a single bundle and listens for file changes to reload this bundle to show the updated code) and Babel (converts ES6 and JSX to plain JavaScript). npx itself is a Node tool which allows you to run a package, in this case with Create React App, which allows you to easily start a new React project. The server that you see is simply to allow for the reloading of the app in response to file changes in real time. The server is only for use in development.