Architecture

How I Built CommerceX: A Scalable MERN Stack Architecture

February 10, 2026
8 min read
Written by Jenil Rupapara

Introduction

Building a scalable e-commerce platform requires careful consideration of architecture, database design, and state management. In this article, I'll walk you through how I built CommerceX, utilizing a microservices approach within a MERN stack environment.

The Problem with Monoliths

When I first started CommerceX, I considered a monolithic architecture. However, as the feature set grew—adding inventory management, order processing, and real-time notifications—it became clear that a decoupled system was necessary.

Key Challenges

  1. Scalability: Scaling the entire app just to handle high traffic on the product page.
  2. Maintainability: A single codebase becoming too complex.
  3. Deployment: Risk of bringing down the whole system for a minor update.

The Solution: Microservices

I decided to split the application into distinct services:

  • Auth Service: Handles JWT authentication and user management.
  • Product Service: Manages catalog, inventory, and search (cached with Redis).
  • Order Service: Processes transactions and order states.
  • Notification Service: Listens for events (using RabbitMQ) to send emails/SMS.

Implementation Details

Here is a look at how I structured the API Gateway to route requests to these services:

// API Gateway Entry Point
const express = require('express');
const proxy = require('express-http-proxy');
const app = express();
 
app.use('/auth', proxy('http://localhost:8001'));
app.use('/products', proxy('http://localhost:8002'));
app.use('/orders', proxy('http://localhost:8003'));
 
app.listen(8000, () => {
    console.log('Gateway running on Port 8000');
});

Performance Optimization

To ensure the platform could handle high concurrency, I implemented several optimizations:

1. Caching with Redis

Product details are cached to reduce database hits.

2. Database Indexing

MongoDB indexes were crucial for query performance.

Pro Tip: Always analyze your query patterns before creating indexes. Over-indexing can slow down write operations.

Conclusion

Migrating to a microservices architecture introduced complexity but significantly improved scalability and fault tolerance. CommerceX is now capable of handling thousands of concurrent users with ease.

View the Project on GitHub

mernmicroservicessystem-design