Angular is a powerful tool for building dynamic HTML pages that communicate with a back-end server. Whether you’re building a high-throughput API, a simple web application, or a microservice, MEAN is the ideal stack for building Node. js applications.

The mean stack is intended to provide a simple and fun starting point for cloud native fullstack javascript applications.
MEAN is a set of Open Source components that together, provide an end-to-end framework for building dynamic web applications; starting from the top (code running in the browser) to the bottom (database). The stack is made up of:

MongoDB : Document database – used by your back-end application to store its data as JSON (JavaScript Object Notation) documents
Express (sometimes referred to as Express.js): Back-end web application framework running on top of Node.js
Angular (formerly Angular.js): Front-end web app framework; runs your JavaScript code in the user’s browser, allowing your application UI to be dynamic
Node.js : JavaScript runtime environment – lets you implement your application back-end in JavaScript