Banking System Backend

A secure and scalable Banking System Backend built using Java and Spring Boot, implementing real-world banking operations with strong focus on security, transaction processing, and business logic.

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Features

Authentication & Security

• User registration and login
• Password encryption using BCrypt
• JWT-based authentication
• Secure REST APIs with token validation

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Account Management

• Create and manage bank accounts
• Fetch account details
• View all accounts

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Core Banking Operations

• Deposit money
• Withdraw money
• Transfer funds between accounts

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Transactions

• Record all transactions (Deposit, Withdraw, Transfer)
• View transaction history per account

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Payments & Cashback

• Payment processing system
• 2% cashback calculation
• Scheduled cashback processing using Spring Scheduler
• Payment status tracking (PENDING / COMPLETED)

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Advanced Features

• Top spenders API (analytics)

• Fraud detection system:

  • Large transfer detection
  • Multiple transactions within short time detection

• Centralized exception handling with structured JSON responses

• Clean layered architecture (Controller → Service → Repository)

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Tech Stack

• Java
• Spring Boot
• Spring Security
• JWT (JSON Web Token)
• Spring Data JPA
• Hibernate
• MySQL
• Maven
• Postman (API Testing)

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Project Structure

src/main/java/net/javalearn/banking

├── controller
├── service
├── service/impl
├── repository
├── entity
├── dto
├── config
├── security
├── exception
├── scheduler

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API Endpoints

Authentication

• POST /api/auth/register
• POST /api/auth/login

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Accounts

• POST /api/accounts
• GET /api/accounts/{id}
• GET /api/accounts

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Transactions

• PUT /api/accounts/{id}/deposit
• PUT /api/accounts/{id}/withdraw
• PUT /api/accounts/transfer
• GET /api/transactions/{accountId}

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Payments

• POST /api/payments/pay
• GET /api/payments/{paymentId}

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Analytics

• GET /api/accounts/top-spenders?n=5

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Authentication

After login, include JWT token in request headers:

Authorization: Bearer <your_token>

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Setup Instructions

1️⃣ Clone the Repository

git clone https://github.com/your-username/banking-system-backend.git
cd banking-system-backend

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2️⃣ Configure Database

Update application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/banking_db
spring.datasource.username=root
spring.datasource.password=your_password
spring.jpa.hibernate.ddl-auto=update

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3️⃣ Run the Application

mvn spring-boot:run

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Testing

Use Postman to test APIs:

1. Register a user
2. Login → receive JWT token
3. Add token in Authorization header
4. Access secured endpoints

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Key Learnings

• Implemented secure authentication using JWT and BCrypt
• Designed real-world banking workflows (transactions, payments, cashback)
• Built scheduler-based background processing
• Implemented fraud detection logic for suspicious transactions
• Structured API responses with proper error handling
• Applied clean architecture and separation of concerns

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Author

Disha Shirbad Backend Developer | Java | Spring Boot

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Project Highlights

• Real-world banking backend system
• Secure authentication & authorization
• Fraud detection implementation
• Scheduler-based cashback processing
• Production-level backend design

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Future Improvements

• Role-based access control (ADMIN/USER)
• Email/OTP verification
• Docker deployment
• Cloud deployment (AWS / Render)