💸 PayZap – A Simple Payment Simulator

PayZap is a lightweight MERN stack-based payment simulation platform that lets users sign up, sign in, manage profiles, and simulate sending or receiving payments — all in a secure, user-friendly environment. Check it out at http://13.51.70.83:5173.

Project Description

PayZap is a full-stack payment simulator built using the MERN stack. It features secure user authentication, transaction simulation, and a responsive user interface inspired by modern fintech platforms. To ensure scalability and high availability, the application is containerized using Docker and deployed on an AWS EC2 instance.The frontend and backend services are set up using Docker Compose. A key feature of the project is the use of NGINX as a load balancer for the backend.

🚀 Features

• User Authentication (JWT-based)
• Profile Management
• Simulated Transactions (Send/Receive Money)
• NGINX Load Balancing & Dockerized Deployment
• MongoDB for persistent data storage
• Responsive UI built with React + TailwindCSS

🛠️ Tech Stack

• React
• Tailwind CSS
• Node.Js
• MongoDB
• Docker
• NGINX
• EC2

Local Set Up

Clone the project:

git clone https://github.com/avirup-ghosal/PayZap.git

Setting Environment Variables:

cd PayZap
cd frontend

Create a env file:

touch .env

Add the following line to it:

VITE_BACKEND_URL=http://localhost:3000

Go to the backend directory:

cd ../backend

Create a file named config.js:

touch config.js

Add your secret inside it:

// backend1/config.js
module.exports = {
  JWT_SECRET: "Your-Secret"
};

🐳 Docker Setup

Start the project with Docker compose:

cd ..
docker compose up

Environment Notes

• VITE_BACKEND_URL is used by the frontend to connect to your backend API.
• JWT_SECRET is used to sign/verify JSON Web Tokens in the backend.
• For production, make sure to store secrets securely using environment variables or secret managers.

NGINX Config file

Write this in your nginx.conf file (/etc/nginx/nginx.conf):

http {
    upstream backend {
        least_conn;  # or use round-robin (default) or ip_hash
        server 127.0.0.1:3000 max_fails=3 fail_timeout=10s;
        server 127.0.0.1:3001 max_fails=3 fail_timeout=10s;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://backend;

            # Recommended headers
            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_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

            # Timeouts
            proxy_connect_timeout 5s;
            proxy_send_timeout 10s;
            proxy_read_timeout 10s;
        }
    }
}

events {}

Start NGINX with:

sudo systemctl restart nginx