Fintech Loan Application Portal

A comprehensive loan calculator and application management system built with enterprise-grade security and scalability in mind. This project demonstrates full-stack development capabilities suitable for fintech and banking environments.

🏗️ Architecture Overview

Backend: Spring Boot 3.x with Java 17, implementing clean architecture patterns
Frontend: React 18 with TypeScript for type-safe, scalable UI development
Database: PostgreSQL with Redis caching for optimal performance
Security: JWT-based authentication with Spring Security, BCrypt password hashing
Testing: Comprehensive test suite with JUnit, Testcontainers, and Cypress
Deployment: Docker containerization with CI/CD pipeline support

🚀 Features

Public Access

Loan Calculator: Interactive tool for calculating monthly payments and amortization schedules
Responsive Design: Mobile-first approach with modern UI/UX

Authenticated Users

Secure Registration/Login: JWT-based authentication with session management
Loan Application Portal: Multi-step form with comprehensive validation
Application Tracking: Real-time status updates and history

Admin Dashboard

Application Management: Review, approve, or reject loan applications
User Management: View and manage user accounts
Audit Trail: Complete logging of all system activities
Analytics Dashboard: Key metrics and reporting

Security & Compliance

OWASP Compliance: Protection against XSS, SQL injection, CSRF
Data Encryption: Sensitive data encryption at rest and in transit
Audit Logging: Comprehensive audit trail for regulatory compliance
Role-Based Access: Granular permissions and access control

🛠️ Quick Start

Prerequisites

Docker and Docker Compose
Java 17+ (for local development)
Node.js 18+ (for local development)

Using Docker (Recommended)

# Clone the repository
git clone <repository-url>
cd loan-portal

# Copy environment variables
cp .env.example .env

# Start all services
docker-compose up -d

# Wait for services to be ready, then access:
# Frontend: http://localhost:3000
# Backend API: http://localhost:8080
# API Documentation: http://localhost:8080/swagger-ui.html

Local Development Setup

# Backend
cd backend
./mvnw spring-boot:run

# Frontend (in another terminal)
cd frontend
npm install
npm start

# Database (PostgreSQL with Docker)
docker run -d --name postgres-loan \
  -e POSTGRES_DB=loanportal \
  -e POSTGRES_USER=admin \
  -e POSTGRES_PASSWORD=admin123 \
  -p 5432:5432 postgres:15

👥 Test Credentials

Role	Email	Password	Capabilities
Admin	admin@loanportal.com	Admin@123	Full system access
User	user@example.com	User@123	Loan applications

📊 Database Schema

Core Tables

users: User account information with encrypted passwords
loan_applications: Comprehensive loan application data
audit_logs: Complete system activity tracking
user_roles: Role-based permission management

Key Relationships

Users can have multiple loan applications
Each application change is logged in audit_logs
Role hierarchy enforces proper access control

🔒 Security Implementation

Authentication & Authorization

JWT Tokens: Stateless authentication with configurable expiration
BCrypt Hashing: Industry-standard password security
Role-Based Access: Granular permission system
Session Management: Secure token refresh and logout

Data Protection

Input Validation: Server and client-side validation
SQL Injection Prevention: Parameterized queries with JPA
XSS Protection: Content Security Policy headers
CSRF Protection: Spring Security CSRF tokens

🧪 Testing Strategy

Backend Testing

cd backend
./mvnw test                    # Unit tests
./mvnw test -Pintegration      # Integration tests
./mvnw verify                  # All tests + code coverage

Frontend Testing

cd frontend
npm test                       # Unit tests
npm run test:e2e              # End-to-end tests
npm run test:coverage         # Coverage report

Test Coverage Goals

Backend: >90% line coverage
Frontend: >85% component coverage
E2E: Critical user journeys covered

📈 Performance & Scalability

Optimization Features

Database Indexing: Optimized queries for loan applications
Redis Caching: Session and calculation result caching
Connection Pooling: HikariCP for database connections
Lazy Loading: Efficient data loading strategies

Monitoring Ready

Health Checks: Spring Actuator endpoints
Metrics: Micrometer integration for monitoring
Logging: Structured logging with correlation IDs

🚀 Deployment

Production Deployment

# Build production images
docker-compose -f docker-compose.prod.yml build

# Deploy to production
docker-compose -f docker-compose.prod.yml up -d

CI/CD Integration

The project includes GitHub Actions workflows for:

Automated testing on pull requests
Security scanning and dependency checks
Docker image building and deployment
Database migration management

📚 API Documentation

Interactive API documentation is available at:

Swagger UI: http://localhost:8080/swagger-ui.html
OpenAPI Spec: http://localhost:8080/v3/api-docs

Key Endpoints

POST /api/auth/login - User authentication
POST /api/loans/calculate - Loan calculation
POST /api/applications - Submit loan application
GET /api/admin/applications - Admin application management

🔧 Development Workflow

Code Quality Standards

Checkstyle: Java code style enforcement
ESLint/Prettier: TypeScript/React code formatting
SonarQube: Code quality and security analysis
Conventional Commits: Standardized commit messages

Git Workflow

Feature branch from develop
Pull request with automated testing
Code review and approval
Merge to develop
Release branches for production deployment

🏢 Enterprise Features

Regulatory Compliance

Audit Trail: Complete activity logging for compliance
Data Retention: Configurable data retention policies
Privacy Controls: GDPR-compliant user data management

Scalability Design

Microservices Ready: Modular architecture for easy scaling
Load Balancer Compatible: Stateless design for horizontal scaling
Database Sharding: Prepared for database scaling strategies

🤝 Contributing

Fork the repository
Create a feature branch
Commit your changes
Push to the branch
Create a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

👨‍💻 About

This project demonstrates enterprise-level full-stack development skills including:

Clean Architecture: Separation of concerns and SOLID principles
Security Best Practices: OWASP compliance and secure coding
Testing Excellence: Comprehensive test coverage and quality assurance
DevOps Integration: Docker, CI/CD, and deployment automation
Documentation: Thorough documentation and API specifications

Perfect for showcasing fintech and banking software engineering capabilities