MEAN stack employs JavaScript code for the frontend, backend, and libraries as well. To become an efficient MEAN stack developer, you first need to master JavaScript concepts and acquire hands-on experience working with this language. A MEAN stack developer is essentially a full-stack web developer with sound knowledge of various programming languages and technology frameworks. They should be experts at MongoDB, Angular.js, Express.js, and Node.js, and also proficient in CSS and HTML. They need to understand the client and server-side technologies and processes and have a basic familiarity with the Git platform and MotionUI framework.