Ashish Kumar props is a concept of React. There is no concept of props in Node.js. server/index.js starts an Express.js server and serves the static content of the build folder which is our entire React application. If you want to pass props, you need to pass from React App itself, from the src/index.js file to the App component, or using App.defaultProps = {some_prop: some_value} inside the src/App.js file.