PaymentX: NFC-Based Offline Payment System

Campus payments made simple, even without internet!

🌟 Overview

PaymentX solves a critical problem in campus environments - making payments in areas with limited internet connectivity. Our solution leverages NFC technology to enable seamless transactions between students and campus merchants without requiring internet on the user's device.

💸 For Students Make payments without internet Link your college ID card via NFC Secure transactions with custom PIN Easy wallet top-up Track transactions (coming soon)

🏪 For Merchants Simple storefront setup Receive payments instantly Comprehensive transaction history Withdraw funds easily Business analytics dashboard

✨ Key Features

🔄 Payment Flow

1. Registration - Sign up with your college email and register your ID card
2. Setup - Create transaction PIN and verify phone number
3. Top-up - Add funds to your PaymentX wallet
4. Tap & Pay - Tap your ID card on merchant's device
5. Verify - Authorize with your secure PIN
6. Complete - Transaction processed instantly!

⚠️ Note: While users can pay offline, merchants require internet connectivity to process transactions.

🛡️ Security Features

🔐 Secure Authentication Multi-factor authentication for all users

🔒 Encrypted Transactions All payment data is fully encrypted

🔢 PIN Protection Custom PIN for authorizing transactions

📶 Secure NFC Tamper-resistant communication

🛠️ Technology Stack

Kotlin

Node.js

MongoDB

JWT

NFC

📱 Application Architecture

System Architecture

┌─────────────────┐      ┌─────────────────┐      ┌─────────────────┐
│                 │      │                 │      │                 │
│   User Mobile   │◄────►│  PaymentX API   │◄────►│ Merchant Mobile │
│   Application   │      │    (Backend)    │      │   Application   │
│                 │      │                 │      │                 │
└─────────────────┘      └────────┬────────┘      └─────────────────┘
                                  │
                                  ▼
                         ┌─────────────────┐
                         │                 │
                         │    MongoDB      │
                         │   Database      │
                         │                 │
                         └─────────────────┘

Mobile Architecture

PaymentX/
├── User App/
│   ├── Authentication
│   │   ├── Registration
│   │   ├── Login
│   │   └── PIN Management
│   ├── Wallet Management
│   │   ├── Top-up
│   │   ├── Balance Check
│   │   └── Withdrawal
│   ├── NFC Integration
│   │   ├── Card Registration
│   │   └── Payment Processing
│   └── Transaction History
│
└── Merchant App/
    ├── Business Registration
    ├── Payment Terminal
    ├── Transaction Dashboard
    └── Withdrawal Management

⚙️ Implementation Status

Component	Status	Details
Merchant App	✅ Complete	Fully implemented with payment receiving functionality
Backend API	✅ Complete	All endpoints implemented and documented
User Authentication	✅ Complete	Email & PIN verification implemented
NFC Integration	✅ Complete	Card registration and payment processing
Merchant Transaction History	✅ Complete	Full history tracking for merchants
User App Core Features	⏳ In Progress	Basic functionality implemented, UI refinements ongoing
User Transaction History	✅ Complete	Implementation planned for next sprint

🚀 Getting Started

Prerequisites

• Android Studio
• Node.js
• MongoDB
• Android device with NFC capability

Installation & Setup

User App Setup

1. Clone this repository

   git clone https://github.com/ISTE-VIT/paymentx-app.git

2. Open the project in Android Studio
3. Connect an NFC-capable Android device
4. Run the application
5. Register with your college email
6. Add your ID card via NFC

Merchant App Setup

1. Follow the same steps as User App
2. Select "Register as Merchant" during setup
3. Enter your business details
4. Ensure your device has active internet connection

Backend Setup

1. Clone the backend repository

   git clone https://github.com/ISTE-VIT/paymentx-backend.git

2. Install dependencies

   cd paymentx-backend
   npm install

3. Set up environment variables

   cp .env.example .env
   # Edit .env with your configuration

4. Start the server

   npm start

🔗 Related Repositories

• PaymentX Backend

👥 Meet Our Team

Rudra Gupta Android Developer

Pratham Khanduja Android & Backend Developer

Saniya Goyal UI/UX Designer

PaymentX

Transforming Campus Payments | Made with ❤️ at ISTE-VIT

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