MERN Stack: An Overview

Written by Coursera Staff • Updated on

Learn more about what MERN stack is and how it operates, the four separate components of MERN stack, its advantages and limitations, as well as how it’s used today.

[Featured image] An app developer is working on their laptop in the office.

MERN stack is a popular JavaScript framework used for building web applications. It is an acronym for MongoDB, Express.js, React, and Node.js. Each component of the stack plays a specific role in the development process. MERN stack, known for its versatility and efficiency, allows developers to build robust and scalable applications using JavaScript.

What is MERN Stack?

MERN stack stands out for its versatility, efficiency, and end-to-end JavaScript implementation when building web applications. It allows developers to leverage a single language, JavaScript, across the entire stack, enabling code reuse and streamlining the development process. Here is a brief explanation of the stack’s four components:  

  • MongoDB provides a flexible and scalable data management solution. 

  • Express.js simplifies writing code and building back-end components for application development. 

  • React, known for its component-based architecture and efficient rendering, empowers developers to build dynamic and interactive user interfaces. 

  • Node.js enables fast and event-driven back-end development, facilitating seamless communication between the front-end and back-end components.

Overall, MERN stack offers a comprehensive and cohesive framework for building full-stack JavaScript applications. It empowers developers to create modern, responsive, and efficient web experiences. The components work harmoniously, combining their strengths to deliver high-performance applications that can handle complex functionalities.

The four components that comprise MERN stack

As mentioned previously, the four components of MERN stack work together to create a cohesive and efficient stack for developing full-stack JavaScript applications. Read on to gain a deeper understanding of each element of the stack.  

1. MongoDB

MongoDB is a NoSQL database that is used as the data storage component in MERN stack. Known for its flexibility and scalability, MongoDB is a great choice to handle large quantities of data. MongoDB stores data in JSON-like documents, which allows for easy integration with JavaScript-based applications. Its query language and data manipulation capabilities make it a powerful tool for managing and retrieving data in MERN applications.

2. Express.js

Express.js is a lightweight web application framework that runs within a Node.js server. It provides features and utilities for building web applications and application programming interfaces (APIs). Express.js simplifies handling HTTP requests, defining routes, and managing middleware. It allows developers to create robust server-side applications quickly and efficiently. Express.js seamlessly integrates with other components of the MERN stack and enables efficient communication between the front end and the back end.

3. React

React is the front-end part of MERN stack and is often a common choice for developing user interfaces (UI). The architecture React builds upon is component-based. This enables developers to make and maintain reusable UI components. It provides a virtual document object model (DOM) that optimizes rendering performance by efficiently updating only the necessary parts of the UI. React's declarative syntax and efficient rendering make it a powerful tool for creating interactive and dynamic web applications.

Read more: What Is a React Developer? (And How to Become One)

4. Node.js

Node.js is a common JavaScript environment. Specifically, it’s a runtime environment, enabling developers to utilize JavaScript code in various places, including outside of a web browser. It serves as the backend component in MERN stack. Node.js provides an event-driven, non-blocking I/O model that is highly scalable and efficient. It allows developers to build server-side applications using JavaScript, enabling code sharing between the front end and back end. Node.js has a vast ecosystem of modules and packages, making it easy to integrate with other technologies and libraries.

How does a MERN Stack operate?

In a MERN stack application, the front end uses React, which handles the UI and user interactions. It’s in charge of developing user-facing  web and mobile applications. You manage failures effectively at this stage and have the ability to reuse code with React. It assists in creating and managing lists, forms, events, and functions effectively.

The server layer is the second tier of the MERN stack, below the React layer, and comprises Express.js and Node.js. This is where URL redirecting and HTTP requests take place. The client tier and database tier are connected by this layer, creating a seamless transition from the top to the bottom.

The final tier of the MERN stack, the database layer, stores your app's data with MongoDB. This layer efficiently stores information until it’s retrieved.

Overall, MERN stack enables the development of full-stack JavaScript applications, where the front end and back end seamlessly work together to provide a complete user experience. The stack leverages the strengths of each component, allowing developers to build efficient, scalable, and responsive web applications.

Examples of MERN stack uses

MERN stack has gained popularity in various domains for web application development. Some examples include:

  • News aggregation apps: Delivering all types of content from various sources to one centralized place for readers.

  • Workflow management tools: Developing collaborative platforms for managing tasks, deadlines, and team communication.

  • Real-time chat applications: Developing chat applications with real-time updates and messaging features.

Advantages of MERN

MERN stack boasts various advantages that make application development on the web more versatile and efficient. Here are some key advantages:

  • Full-stack JavaScript: MERN stack allows developers to use a single programming language, JavaScript, throughout the entire application stack, both front and back end. This enables code reuse, streamlines development, and simplifies the learning curve for JavaScript developers.

  • Efficient development: MERN stack offers a cohesive and integrated set of tools, allowing for rapid application development. The use of React for the front end enables efficient rendering and component reusability, while Node.js facilitates scalable and event-driven server-side development.

  • Versatility: With MongoDB as the NoSQL database, MERN stack provides flexibility in handling data and scaling applications as per requirements.

  • Active community and ecosystem: MERN stack has a vibrant and active community, which means ample resources, libraries, and community-driven support are available for developers. This makes it easier to find solutions, learn new techniques, and stay updated with best practices.

Read more: How to Become a Web Developer

Limitations of MERN

Like any technology stack, MERN stack has its limitations. Here are a couple of key limitations to consider:

  • Performance considerations: While React's efficient rendering contributes to high-performance user interfaces, improper handling of data or lack of optimization in the back end can impact overall application performance. Careful design and implementation are crucial to achieving optimal performance in MERN applications.

  • Scalability challenges: Although MERN stack is scalable, as the application grows and user traffic increases, additional considerations and architectural decisions may arise to ensure efficient scaling of both front-end and back-end components.

Alternatives to MERN stack

While MERN stack is widely used and versatile, alternative technology stacks exist for web development. Some popular alternatives include:

Alternative stackDescription
MEAN stackSimilar to MERN, but replaces React with Angular for front-end development.
LAMP stackUses Linux as the operating system, Apache as the web server, MySQL as the database, and PHP as the back-end scripting language.
Ruby on Rails stackA framework built using the Ruby programming language that facilitates full-stack web development
DjangoA Python-based web development framework known for its scalability and rapid development capabilities.

Tips on how to learn MERN

Finding the right place to start learning MERN stack and other similar technologies takes time and effort. Utilize the tips below to start your journey into becoming a MERN stack expert:

  1. JavaScript fundamentals: Start by gaining a solid understanding of JavaScript, as it forms the foundation for the entire MERN stack.

  2. Online tutorials and courses: Take advantage of the numerous online tutorials and courses available that specifically focus on MERN stack. Platforms like Coursera, offer comprehensive resources.

  3. Practical projects: Build small projects to apply your knowledge and gain hands-on experience with each component of MERN stack. These small projects can build your overall confidence in the abilities you have.

  4. Documentation and community resources: Refer to the official documentation for MongoDB, Express.js, React, and Node.js. They provide in-depth information about each component, including guides, API references, and tutorials. Additionally, engage with the MERN stack community through forums, online communities, and developer groups. These resources can provide valuable insights, tips, and solutions to common challenges.

Getting started with Coursera

If you’re interested in learning more about MERN stack, completing a course or receiving a relevant certificate is a great place to start. On Coursera, you can enroll in some of the top development courses in the world.

  • If you’re interested in learning more about related topics and diving into a more specialized course, consider enrolling in Introduction to iOS Mobile Application Development offered by Meta. The estimated time to complete this course is 11 hours and it features flexible deadlines. This course is entirely online and is offered at a beginner level as well. 

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