Let’s Learn MERN Stack

Shanuka Prabodha Deshapriya
4 min readMar 2, 2021


Technology growing rapidly every day.MERN is the most popoular technology used in nowadays because it easy to use and manage.MERN stack uses main language as a JavaScript. Let’s try to unserstand each one by one.

What is MERN Stack?

A stack is collection of technologies used to create a web application. The MERN is a JavaScript stack. It is a most popular technology for creating web applications. MERN stands for MongoDB, Express, React, Node.

· MongoDB — document base NoSQL database

· Express(.js) — Node.js web application framework

· React(.js) — client-side JavaScript framework (Front-end)

· Node(.js) — JavaScript runtime environment

How does the MERN stack acts?


A database, meaning a structured way to store and access data, more specifically, MongoDB is NoSQL (non-relational) document database .it doesn’t use tables of data. This means that data is stored as JSON like documents.MongoDB can use anytime when developer want.

Comparing Terminology

Features of MongoDB

· High performance :-

I/O activity

Faster queries

· High Availability :-

Replica set

· Horizontal scalability :-


· Support for Multiple Storage Engines :-

WiredTiger Storage Engine

In-Memory Storage Engine

Mongo Db Atlas :- The global cloud database.

Document :- A way to organize and store data as a set of field-value pairs.

Replica set :- Group of MongoDB servers that maintain the same dataset ,providing redundancy and increasing data availability.

Sharding :- Method for distributing data across multiple machines


Express is open-source web application framework for Node.js, that means the codes are already written for programming. It’s for back end application. Without any effort developer can used for designing and building web apps easily. It is used for develop a single page, multi-page or hybrid web applications. JavaScript is most widely used language that supports express.js, then it will be increase the programming efficiency for build web applications in a short period of time.


React is most famous front-end JavaScript library for building web applications. It is open-source and used for building user interfaces especially for single-page applications. When using react ,web pages does not reload and only the essential part will be re-rendered. It happens beacause react has specific algorithm which is sensitive to apply changes in the components.React uses immutability concept.

In React ,everything is a component and it is famous for implementig a vitual DOM.


· React uses virtual DOM that is a JS object. It will improve the performance.

· It can be used on client and sever side as well as other frameworks.


Node.js is a JavaScript runtime environment which can run code on the sever side. It is so popular because it uses JavaScript .It uses asynchronous programming and V8 JavaScript engine. Features of Node.js : use non -blocking I/O ,event driven ,very fast and no buffering.

NPM — Node package Manger

NPM is the default package manager for Node.js. Developers can use it to install libraries to make their works easier.

This is not complete information but I hope it’s enough you to get brief idea about MERN.

Thanks for reading !…