Loan Management System - Backend API

A comprehensive RESTful API for microfinance/lending management built with Node.js and MySQL.

🚀 Live Demo

API Endpoint: https://loan-management-backend-h2d1.onrender.com

Note: Demo deployment uses free-tier hosting. Production deployment will be handled by the client with proper infrastructure.

📋 Overview

Enterprise-grade loan management system backend designed for microfinance institutions. Handles borrower management, loan processing, EMI calculations, payment tracking, and analytics.

Key Capabilities

• Secure JWT-based authentication with refresh tokens
• Automated EMI calculation and installment scheduling
• Role-based access control (Admin/Super Admin)
• RESTful API architecture
• Payment collection and late fee management
• Real-time dashboard analytics
• SMS notification integration

🛠️ Tech Stack

• Runtime: Node.js + Express.js
• Database: MySQL
• Authentication: JWT (jsonwebtoken)
• Security: bcrypt password hashing, helmet, cors
• Validation: express-validator
• Environment: dotenv

📁 Project Structure

backend/
├── config/          # Database and app configuration
├── controllers/     # Business logic handlers
├── middleware/      # Authentication & validation
├── routes/          # API route definitions
├── utils/           # Helper functions (JWT, calculations)
├── server.js        # Application entry point
└── package.json     # Dependencies

🔧 Environment Setup

Required Environment Variables

NODE_ENV=production
PORT=5000
API_VERSION=v1

# Database Configuration
DATABASE_URL=mysql://user:password@host:port/database

# JWT Configuration
JWT_SECRET=your_secret_key_here
JWT_REFRESH_SECRET=your_refresh_secret_here
JWT_EXPIRES_IN=24h
JWT_REFRESH_EXPIRES_IN=7d

# Security
BCRYPT_ROUNDS=10
CORS_ORIGIN=https://yourdomain.com

⚠️ Security Note: Never commit .env files. Use environment variable management in production.

🚦 Installation & Setup

Prerequisites

• Node.js (v14 or higher)
• MySQL (v8.0 or higher)
• npm or yarn

Local Development

# Clone the repository
git clone https://github.com/seshathri044/loan-management-backend.git
cd loan-management-backend

# Install dependencies
npm install

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

# Run database migrations (if applicable)
npm run migrate

# Start development server
npm run dev

📡 API Documentation

Authentication Endpoints

POST   /api/v1/auth/register     - Admin registration
POST   /api/v1/auth/login        - Admin login
POST   /api/v1/auth/refresh      - Refresh access token
PUT    /api/v1/auth/profile      - Update profile
PUT    /api/v1/auth/password     - Change password

Borrower Management

GET    /api/v1/borrowers         - List all borrowers
POST   /api/v1/borrowers         - Create borrower
GET    /api/v1/borrowers/:id     - Get borrower details
PUT    /api/v1/borrowers/:id     - Update borrower
DELETE /api/v1/borrowers/:id     - Delete borrower

Loan Management

GET    /api/v1/loans             - List all loans
POST   /api/v1/loans             - Create loan
GET    /api/v1/loans/:id         - Get loan details
PUT    /api/v1/loans/:id         - Update loan
GET    /api/v1/loans/:id/schedule - Get installment schedule

Payment Collection

POST   /api/v1/payments          - Record payment
GET    /api/v1/payments/loan/:id - Get payment history

Analytics Dashboard

GET    /api/v1/dashboard/stats   - Get dashboard statistics
GET    /api/v1/dashboard/analytics?period=daily - Period-wise analytics

🔐 Security Features

• JWT access & refresh token mechanism
• Bcrypt password hashing (configurable rounds)
• CORS protection
• Helmet security headers
• Input validation and sanitization
• SQL injection prevention
• Rate limiting (recommended for production)

🏗️ Architecture

Client (Flutter App)
    ↓
Express.js API Server (Render)
    ↓
MySQL Database (Railway)

📊 Database Schema

Key tables:

• admins - Admin user management
• borrowers - Borrower information
• loans - Loan details and status
• installments - EMI schedule
• payments - Payment transactions

🚀 Deployment

Render (Current Demo)

# Build command
npm install

# Start command
npm start

Production Deployment Checklist

• Set NODE_ENV=production
• Configure production database
• Set strong JWT secrets
• Configure CORS for specific domain
• Enable SSL/TLS
• Set up monitoring and logging
• Configure backup strategy
• Implement rate limiting
• Set up CDN (if needed)

🧪 Testing

# Run tests (when implemented)
npm test

# Run linting
npm run lint

📦 Dependencies

{
  "express": "^4.18.x",
  "mysql2": "^3.x.x",
  "jsonwebtoken": "^9.x.x",
  "bcrypt": "^5.x.x",
  "dotenv": "^16.x.x",
  "cors": "^2.x.x",
  "helmet": "^7.x.x",
  "express-validator": "^7.x.x"
}

🤝 Integration

This backend is designed to work with:

• Frontend: Flutter mobile application
• Platform: Android & iOS
• Frontend Repository: (Link if public)

📝 Development Notes

• Free-tier hosting may experience cold starts (10-30s initial response)
• Production deployment will use dedicated infrastructure
• API versioning implemented for future compatibility
• Modular architecture for easy feature additions

🏢 Project Status

• Status: Production-ready
• Client: Vyugam Solutions
• Purpose: Portfolio demonstration & client handoff
• License: Proprietary

🔗 Links

• Live API: https://loan-management-backend-h2d1.onrender.com
• Company: Vyugam Solutions
• APK Release: Download v1.0.0

📧 Contact

For inquiries regarding this project, please contact through Vyugam Solutions.

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⚠️ Disclaimer: This is a demonstration deployment. The live API uses non-sensitive test data. Production deployment will be handled by the client with appropriate security measures and infrastructure.