Express.js is a back-end web application framework for Node.js. It simplifies the process of creating robust and scalable server-side applications by providing essential features like routing, middleware, and HTTP utilities.

React is a popular front-end JavaScript library for building user interfaces. It allows developers to create reusable components and efficiently manage the application's state, resulting in a highly interactive and efficient user experience.

Node.js is a JavaScript runtime environment that enables server-side development using JavaScript. It allows developers to use the same language for both front-end and back-end development, facilitating seamless communication between the client and server.

npm is the default package manager for Node.js and is used to install, manage, and update packages and dependencies required for the MERN stack development.

Webpack is a module bundler that helps bundle and manage various assets, such as JavaScript files, CSS, and images, for efficient delivery to the browser.

Babel is a transpiler that allows developers to write modern JavaScript code and convert it into older versions to ensure compatibility with older browsers.

Axios and Fetch are JavaScript libraries used to make HTTP requests to the back-end server to fetch and send data to and from the front-end.

Redux is a state management library that is commonly used with React to manage the application's state in a predictable and centralized way.

Passport.js is a popular authentication middleware used to implement user authentication and session management in Express.js applications.