What is MERN Stack?

MERN stack is the combination of MongoDB, Express, React, and Node.js. In this article, I’ll take you through what is Mern Stack? How it is used in Web Development and an overview of the technologies that make up the MERN stack. 

The process of Web development has changed today, it is not what it was a few years ago. We now have so many options and the uninitiated often don’t know what is the best one for them. This applies not only to the whole but also to the tools that help in web development as there are so many choices today. MERN Stack is one of the best options from those choices.

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Introduction to MERN Stack

Before MERN Stack let’s understand what is a stack. Any web application or framework is created by using a lot of technologies. The combination of all those technologies is called a stack, popularized by the LAMP stack, which is a combination Linux, Apache, MySQL, and PHP, all of which are open source components.

As web development matured and interactivity became more popular, Single Page Applications (SPAs) became more popular. A SPA is a web application paradigm that avoids refreshing a web page to display new content; instead, it uses light calls to the server to get data or extracts and updates the web page.

The result looks pretty neat compared to the old way of fully reloading the page. This has resulted in an increase in front-end frameworks as much of the work has been done on the client-side. Around the same time, although completely independent, NoSQL databases also started to gain popularity.

The MEAN stack (MongoDB, Express, AngularJS, Node.js) was one of the first open-source stacks to embody this shift to SPAs and NoSQL adoption. AngularJS, a front-end framework based on the Model-View-Controller (MVC) design model, anchored this stack. MongoDB, a very popular NoSQL database, has been used for persistent data storage.

Node.js, a server-side JavaScript runtime environment, and Express, a web server built on top of Node.js, formed the middle tier or web server. This stack is arguably the most popular stack for any new web application these days.

Not exactly in competition, but React, an alternative front-end technology from Facebook is growing in popularity and offering a replacement for AngularJS. It thus replaces the “A” by an “R” on AVERAGE, to give us the MERN Stack.

Components of MERN Stack

Hope you now know what the MERN stack is and how it is used in very large scale web development today. In this section, I will introduce you to the components of MERN Stack.


MongoDB is a very popular database used in the MERN stack. In simple words, it is a database which facilitates online storage. It is a NoSQL document-oriented database, with flexible schema and JSON-based query language.


Express is the framework that simplifies the task of writing your server code. The Express framework allows you to define routes, specifications on what to do when an HTTP request matching a certain pattern arrives.


React anchors the MERN stack. In a sense, this is the defining component of the MERN stack. React is an open-source JavaScript library maintained by Facebook that can be used to create views rendered in HTML.

Unlike AngularJS, React is not a framework. It’s a library. Thus, it does not by itself dictate a framework model such as the MVC model. You use React to render a view (the V in MVC), but how to link the rest of the app is entirely up to you.


Node.js is JavaScript outside of a browser. The creators of Node.js just used Chrome’s V8 JavaScript engine and made it work independently as a JavaScript runtime engine. If you are familiar with the Java runtime that runs Java programs, you can easily associate with the JavaScript runtime: the Node.js runtime runs JavaScript programs.

Hope you liked this article on an introduction to MERN Stack commonly used for web development. Please feel free to ask your valuable questions in the comments section below.

Aman Kharwal
Aman Kharwal

I'm a writer and data scientist on a mission to educate others about the incredible power of data📈.

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