🚀 MERN Stack Application — AWS EC2 Deployment Guide

A complete step-by-step guide to deploying a full-stack MERN (MongoDB Atlas, Express, React, Node.js) application on an AWS EC2 instance with Nginx as a reverse proxy and PM2 as a process manager.

---

📋 Table of Contents

• Tech Stack
• Prerequisites
• EC2 Instance Setup
• Clone Your Project
• Backend Setup
• Run Backend with PM2
• Frontend Build
• Install & Configure Nginx
• Verify Deployment
• Accessing Your App
• Updating Your App Remotely
• Common Mistakes
• Quick Reference
• Project Structure

---

🛠 Tech Stack

Layer	Technology
Frontend	React.js
Backend	Node.js + Express.js
Database	MongoDB Atlas (Cloud)
Process Manager	PM2
Web Server / Proxy	Nginx
Cloud Platform	AWS EC2 (Ubuntu / Amazon Linux 2)
Auth	JWT (JSON Web Tokens)

---

✅ Prerequisites

Before you begin, make sure you have:

• An AWS account with EC2 access
• A MongoDB Atlas account with a cluster created
• Your project pushed to a GitHub repository
• A .pem key pair file downloaded from AWS
• EC2 Security Group configured with these inbound rules:

Type	Protocol	Port	Source
SSH	TCP	22	Your IP
HTTP	TCP	80	0.0.0.0/0
Custom TCP	TCP	5000	0.0.0.0/0

---

☁️ MongoDB Atlas Setup

1. Go to https://cloud.mongodb.com → Create free account
2. Create a FREE cluster (M0 Sandbox)
3. Database Access → Add DB User (username + strong password)
4. Network Access → Add IP Address → Allow from Anywhere (0.0.0.0/0)
5. Connect → Drivers → Copy your connection string

# Your connection string will look like:
mongodb+srv://<username>:<password>@cluster0.xxxxx.mongodb.net/<dbname>?retryWrites=true&w=majority

---

📌 Phase 1 — EC2 Instance Setup

# SSH into your EC2 instance
ssh -i your-key.pem ubuntu@<YOUR-EC2-PUBLIC-IP>

# Switch to superuser
sudo su

# Update system packages
apt update -y           # Ubuntu / Debian
# OR
yum update -y           # Amazon Linux

# Verify your current directory and user
pwd
whoami

# Install Node.js 18
curl -fsSL https://rpm.nodesource.com/setup_18.x | sudo bash -
sudo apt install -y nodejs     # Ubuntu
# OR
sudo yum install -y nodejs     # Amazon Linux

# Install Git
sudo apt install -y git        # Ubuntu
# OR
sudo yum install -y git        # Amazon Linux

# Verify installations
node -v
npm -v
git --version

---

📌 Phase 2 — Clone Your Project

# Navigate to home directory
cd ~

# Clone your GitHub repository
git clone https://github.com/<your-username>/<your-repo>.git

# Verify it cloned successfully
ls

# Enter the project folder
cd <your-repo>/
ls

---

📌 Phase 3 — Backend Setup

# Navigate to backend folder
cd <your-backend-folder>/

# Check folder contents
ls

# Install backend dependencies
npm install

# Set up environment variables
cp .env.example .env          # Copy the example file
nano .env                     # Edit and fill in your actual values

Your .env file should contain:

PORT=5000
MONGODB_URI=mongodb+srv://<user>:<pass>@cluster0.xxxxx.mongodb.net/ecommercedb
JWT_SECRET=your_super_secret_jwt_key_here
NODE_ENV=production

# (Optional) Import seed / sample data
npm run data:import

# Test that the backend starts correctly
npm start
# ✅ You should see: "Server running on port 5000"
# ✅ You should see: "MongoDB Atlas Connected"
# Press Ctrl+C to stop — we'll use PM2 next

---

📌 Phase 4 — Run Backend with PM2

# Install PM2 globally
sudo npm install -g pm2

# Navigate to folder containing server.js
cd <your-backend-folder>/

# Start the backend with PM2
pm2 start server.js --name backend

# Save the PM2 process list
pm2 save

# Generate PM2 startup script (auto-restart on server reboot)
pm2 startup

# ⚠️ PM2 will print a command — copy and run it. It looks like:
sudo env PATH=$PATH:/usr/bin /usr/lib/node_modules/pm2/bin/pm2 \
startup systemd -u ubuntu --hp /home/ubuntu

# Save again after running the startup command
pm2 save

# Verify the backend is running
pm2 list
pm2 logs

Expected pm2 list output:

┌─────┬──────────┬─────────┬───────┬──────────┬──────┐
│ id  │ name     │ mode    │ ↺     │ status   │ cpu  │
├─────┼──────────┼─────────┼───────┼──────────┼──────┤
│ 0   │ backend  │ fork    │ 0     │ online   │ 0%   │
└─────┴──────────┴─────────┴───────┴──────────┴──────┘

---

📌 Phase 5 — Frontend Build

# Navigate to frontend folder
cd ~/<your-repo>/<your-frontend-folder>/

# Install frontend dependencies
npm install

# Build for production
npm run build

# Verify build output folder was created
ls
# ✅ You should see a /build or /dist folder

Note: React apps output to /build, while Vite apps output to /dist. Check which one your project uses.

---

📌 Phase 6 — Install & Configure Nginx

Install Nginx

# Ubuntu / Debian
sudo apt install nginx -y

# Amazon Linux
sudo yum install nginx -y

# Start and enable Nginx
sudo systemctl start nginx
sudo systemctl enable nginx        # Auto-start on every reboot

# Check Nginx is active
sudo systemctl status nginx

Configure Nginx

# Open the default config file
sudo nano /etc/nginx/sites-available/default

Replace the contents with:

server {
    listen 80;
    server_name <YOUR-EC2-PUBLIC-IP>;

    # ✅ Serve React frontend
    # Use /build for Create React App or /dist for Vite
    root /home/ubuntu/<your-repo>/<your-frontend-folder>/dist;
    index index.html;

    # ✅ Handle React Router (SPA fallback)
    location / {
        try_files $uri $uri/ /index.html;
    }

    # ✅ Proxy all /api requests to Express backend
    location /api/ {
        proxy_pass http://localhost:5000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_cache_bypass $http_upgrade;
    }
}

# Save and exit: Ctrl+X → Y → Enter

# ✅ Test Nginx configuration for syntax errors
sudo nginx -t

# Expected output:
# nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
# nginx: configuration file /etc/nginx/nginx.conf test is successful

# Restart Nginx to apply the new configuration
sudo systemctl restart nginx

---

📌 Phase 7 — Verify Everything Works

# ✅ Check PM2 backend status
pm2 list
pm2 logs

# ✅ Check Nginx status
sudo systemctl status nginx

# ✅ Check Nginx error logs (if something looks wrong)
sudo tail -f /var/log/nginx/error.log

# ✅ Check Nginx access logs
sudo tail -f /var/log/nginx/access.log

---

📌 Phase 8 — Access Your App

Once everything is running, open a browser and visit:

http://<YOUR-EC2-PUBLIC-IP>          →  React Frontend
http://<YOUR-EC2-PUBLIC-IP>/api/     →  Express Backend API

💡 To use a domain name instead of an IP, point your domain's DNS A record to your EC2 Public IP and update server_name in your Nginx config.

---

🔄 Updating Your App Remotely

When you push new code changes, follow these steps to redeploy:

# 1. SSH into your EC2 instance
ssh -i your-key.pem ubuntu@<EC2-IP>

# 2. Navigate to project folder
cd ~/<your-repo>/

# 3. Pull the latest code
git pull origin main

# 4. Update backend dependencies (if package.json changed)
cd <your-backend-folder>/
npm install

# 5. Restart backend with PM2
pm2 restart backend

# 6. Rebuild the React frontend
cd ~/<your-repo>/<your-frontend-folder>/
npm install
npm run build

# 7. Restart Nginx
sudo systemctl restart nginx

# 8. Confirm everything is live
pm2 list
sudo systemctl status nginx

---

⚠️ Common Mistakes to Avoid

❌ Mistake	✅ Fix
Forgetting to fill in .env	Always run cp .env.example .env and edit every value
Wrong build folder path in Nginx	Check if your output folder is /build (CRA) or /dist (Vite)
Port 5000 not accessible	Add Custom TCP 5000 inbound rule in EC2 Security Group
PM2 not surviving reboot	Always run pm2 startup + pm2 save after starting
Nginx config syntax error	Always run sudo nginx -t before restarting Nginx
Running npm start directly	Use PM2 — npm start blocks terminal and stops on exit
MongoDB IP not whitelisted	In Atlas: Network Access → Add 0.0.0.0/0
Frontend calling wrong API URL	Set REACT_APP_API_URL in frontend .env correctly
Cloning into wrong directory	Always clone into home directory ~ then cd into it

---

📋 Quick Reference Cheat Sheet

Task	Command
SSH into EC2	ssh -i key.pem ubuntu@<EC2-IP>
Check logged-in user	whoami
Update system	apt update -y
Clone repository	git clone <github-url>
Pull latest code	git pull origin main
Install packages	npm install
Seed database	npm run data:import
Build frontend	npm run build
Start app with PM2	pm2 start server.js --name backend
Restart PM2 app	pm2 restart backend
View PM2 process list	pm2 list
View PM2 logs	pm2 logs
Stop PM2 app	pm2 stop backend
Set PM2 auto-start	pm2 startup then pm2 save
Test Nginx config	sudo nginx -t
Restart Nginx	sudo systemctl restart nginx
Check Nginx status	sudo systemctl status nginx
View Nginx error log	sudo tail -f /var/log/nginx/error.log
Edit Nginx config	sudo nano /etc/nginx/sites-available/default

---

📁 Project Structure

your-repo/
├── your-backend-folder/
│   ├── server.js            ← PM2 starts this
│   ├── package.json
│   ├── .env                 ← Fill this in on EC2
│   ├── .env.example         ← Template for .env
│   ├── config/
│   │   └── db.js            ← MongoDB Atlas connection
│   ├── models/
│   ├── routes/
│   ├── middleware/
│   └── seed.js / data/      ← Sample data importer
│
└── your-frontend-folder/
    ├── package.json
    ├── src/
    └── dist/ or build/      ← Nginx serves this folder

---

🔐 Default Credentials (After Seeding)

Admin:   admin@shop.com   /  Admin@1234
User:    user@shop.com    /  User@1234

⚠️ Change these immediately after your first login in production!

---

📞 Troubleshooting

Backend not starting?

pm2 logs          # Check for errors
node server.js    # Run directly to see full error output

Frontend showing blank page?

# Check Nginx root path is correct
sudo nano /etc/nginx/sites-available/default
# Verify the /dist or /build folder actually exists
ls ~/<your-repo>/<your-frontend-folder>/

MongoDB connection refused?

# Check .env has correct MONGODB_URI
cat .env
# Check MongoDB Atlas Network Access allows 0.0.0.0/0

Nginx showing 502 Bad Gateway?

# Backend is not running — check PM2
pm2 list
pm2 restart backend

---

👤 Author

Deployed on AWS EC2 using MongoDB Atlas, PM2, and Nginx.

---

📄 License

This project is licensed under the MIT License.