🏦 Bank Transaction System

A secure and scalable RESTful Banking API built with Node.js, Express, and MongoDB. It supports user authentication, account management, and transaction handling with email notifications.

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🚀 Features

• ✅ User Registration & Login
• 🔐 JWT-based Authentication with secure HTTP-only Cookies
• 🔑 Password Hashing using bcryptjs
• 💸 Bank Transaction Management (Deposit, Withdrawal, Transfer)
• 📧 Email Notifications via Nodemailer (OAuth2)
• 🌱 Environment Variable Support with dotenv
• 🗄️ MongoDB Database Integration via Mongoose

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🛠️ Tech Stack

Technology	Purpose
Node.js	Runtime Environment
Express.js v5	Web Framework
MongoDB + Mongoose	Database
bcryptjs	Password Hashing
JSON Web Token (JWT)	Authentication
Nodemailer + OAuth2	Email Notifications
cookie-parser	Cookie Handling
dotenv	Environment Variables

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📁 Project Structure

Bank_Transaction_system/
├── src/
│   ├── controllers/
│   ├── models/
│   ├── routes/
│   └── middleware/
├── server.js
├── package.json
├── .env
└── .gitignore

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⚙️ Installation & Setup

1. Clone the Repository

git clone https://github.com/raimaAsghar/Bank_Transaction_system.git
cd Bank_Transaction_system

2. Install Dependencies

npm install

3. Configure Environment Variables

Create a .env file in the root directory and add the following:

# Server
PORT=5000

# MongoDB
MONGO_URI=your_mongodb_connection_string

# JWT
JWT_SECRET=your_jwt_secret_key

# Email (OAuth2)
EMAIL_USER=your_email@gmail.com
CLIENT_ID=your_google_client_id
CLIENT_SECRET=your_google_client_secret
REFRESH_TOKEN=your_oauth2_refresh_token

4. Run the Application

# Development mode (with nodemon)
npm run dev

# Production mode
npm start

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📧 Email Setup (Nodemailer + OAuth2)

This project uses Gmail OAuth2 for sending email notifications.

Steps to get OAuth2 credentials:

1. Go to Google Cloud Console and enable the Gmail API.
2. Create OAuth 2.0 Client ID credentials (Web Application type).
3. Add https://developers.google.com/oauthplayground as an Authorized Redirect URI.
4. Go to OAuth 2.0 Playground:
   • Use your own credentials (gear icon → settings).
   • Select scope: https://mail.google.com/
   • Click Authorize APIs → Exchange authorization code for tokens.
   • Copy the Refresh Token.
5. Add all credentials to your .env file.

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🔒 Security Features

• Passwords are hashed with bcryptjs before storing in the database.
• Authentication is handled via JWT tokens stored in secure HTTP-only cookies.
• Sensitive credentials are managed through environment variables.
• .env file is excluded from version control via .gitignore.

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📦 Dependencies

{
  "bcryptjs": "^3.0.3",
  "cookie-parser": "^1.4.7",
  "dotenv": "^17.2.3",
  "express": "^5.2.1",
  "jsonwebtoken": "^9.0.3",
  "mongoose": "^9.1.5",
  "nodemailer": "^7.0.12"
}

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👩‍💻 Author

Raima Asghar GitHub

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📚 References & Acknowledgements

• Nodemailer OAuth2 setup reference: Difference-Backend-documentation by Ankur
• Nodemailer Official Documentation
• Google OAuth2 Documentation
• OAuth 2.0 Playground