🏦 Neptune Bank - Online Banking System

A secure, scalable, and microservices-based online banking platform built using Spring Boot 3.5, Java 21, PostgreSQL, and RabbitMQ.

Neptune Bank provides a complete digital banking solution with user onboarding, KYC verification, account management, secure fund transfers, transaction tracking, OTP-based verification, and JWT-based authentication.

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🚀 Features

👤 User Management

• User Registration with KYC verification
• Profile Management (CRUD Operations)
• Soft Delete Support
• Contact & Nominee Management
• Employee-based KYC Verification

🏦 Account Management

• Savings Account
• Current Account
• Fixed Deposit Account
• Branch Association
• Balance Management
• Optimistic Locking Support

💸 Fund Transfers

• Account-to-Account Transfers
• RabbitMQ-based Processing
• Automatic Rollback on Failures
• Transaction Tracking

📜 Transaction History

• Complete Audit Trail
• Account-wise History
• Chronological Ordering
• Status Tracking

🔐 Security

• JWT Authentication (RS256)
• RSA Key Pair Signing
• BCrypt Password Hashing
• Spring Security Integration
• Role-Based Access Control (RBAC)

📱 OTP Verification

• SMS OTP via TextBee API
• Email OTP via SMTP
• OTP Expiry Management
• Verification Tracking

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🛠 Technology Stack

Category	Technology
Language	Java 21
Framework	Spring Boot 3.5.5
Build Tool	Gradle
Database	PostgreSQL 16
ORM	Spring Data JPA / Hibernate
Messaging	RabbitMQ
Authentication	JWT (RS256)
Security	Spring Security
Password Hashing	BCrypt
Mail Service	Spring Mail
SMS Gateway	TextBee API

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🏗 Microservices Architecture

The system consists of five independent microservices.

Service	Port	Responsibility
Auth Service	8086	Authentication & JWT
User Service	8080	User Profiles & KYC
OTP Service	8082	OTP Generation & Verification
Account Service	8083	Account Management
Transaction Service	8084	Fund Transfers & Transactions

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System Architecture

                       ┌─────────────────┐
                       │     Client      │
                       └────────┬────────┘
                                │
                                ▼
                    ┌─────────────────────┐
                    │     Auth Service    │
                    │      Port 8086      │
                    └────────┬────────────┘
                             │ JWT
                             ▼

 ┌─────────────────┐    RabbitMQ    ┌─────────────────┐
 │  User Service   │◄──────────────►│ Account Service │
 │    Port 8080    │                │    Port 8083    │
 └─────────────────┘                └────────┬────────┘
                                              │
                                              ▼
                                     ┌─────────────────┐
                                     │Transaction Svc │
                                     │    Port 8084   │
                                     └────────┬───────┘
                                              │
                                              ▼
                                     ┌─────────────────┐
                                     │   OTP Service   │
                                     │    Port 8082    │
                                     └─────────────────┘

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🔄 RabbitMQ Communication

Queues

Queue Name	Producer	Consumer
user-validation-queue	account-service	user-service
account-validation-queue	transaction-service	account-service
account-debit-queue	transaction-service	account-service
account-credit-queue	transaction-service	account-service

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🔑 Authentication Flow

Client Login
     │
     ▼
Auth Service
     │
     ▼
Validate Credentials
     │
     ▼
Generate JWT Token
     │
     ▼
Return JWT
     │
     ▼
Use JWT for API Requests

JWT Payload

{
  "sub": "john_doe",
  "role": "USER",
  "iat": 1718150400,
  "exp": 1718161200
}

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👥 User Roles

Role	Access
ADMIN	Full System Access
EMPLOYEE	KYC Verification & Customer Management
USER	Banking Operations

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📂 Services

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🔐 Auth Service (Port 8086)

Responsibilities

• Login Authentication
• JWT Generation
• User Credential Management
• Role Assignment

Endpoints

POST /auth/login
POST /auth/add-user
GET  /auth/validate

Login Request

{
  "username": "john_doe",
  "password": "password123",
  "mode": "jwt"
}

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👤 User Service (Port 8080)

Responsibilities

• User Registration
• Profile Management
• KYC Document Management
• Nominee Management

KYC Documents Supported

• Aadhaar
• PAN
• Passport
• Voter ID
• Driving License
• User Photograph
• Signature

Endpoints

POST   /auth/user
GET    /auth/user/{id}
GET    /auth/users
PUT    /auth/user/{id}
DELETE /auth/user/{id}
GET    /auth/user/exists/{id}

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🏦 Account Service (Port 8083)

Responsibilities

• Account Creation
• Balance Management
• Branch Management
• Account Validation

Supported Account Types

SAVINGS
CURRENT
FIXED_DEPOSIT

Endpoints

POST   /api/accounts/create
GET    /api/accounts/get/{id}
GET    /api/accounts/get/all
GET    /api/accounts/user/{userId}
GET    /api/accounts/number/{number}
PUT    /api/accounts/update/{id}
DELETE /api/accounts/delete/{id}

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💸 Transaction Service (Port 8084)

Responsibilities

• Fund Transfers
• Transaction Tracking
• Audit Trail

Endpoints

POST /transactions/create
POST /transactions/transfer
GET  /transactions/{transactionId}
GET  /transactions/account/{accountId}
GET  /transactions/all

Fund Transfer Workflow

Validate Accounts
       │
       ▼
Create Transaction (PENDING)
       │
       ▼
Debit Source Account
       │
       ▼
Credit Destination Account
       │
       ▼
Success

Rollback Strategy

Debit Success
      │
      ▼
Credit Failed
      │
      ▼
Refund Source Account
      │
      ▼
Mark Transaction Failed

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📱 OTP Service (Port 8082)

Responsibilities

• OTP Generation
• OTP Verification
• SMS Delivery
• Email Delivery

Endpoints

POST /api/otp/send
POST /api/otp/verify

OTP Properties

Property	Value
Length	6 Digits
Generator	SecureRandom
Expiry	5 Minutes
Usage	One Time

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🗄 Database Setup

Create the following databases:

CREATE DATABASE AuthDB;
CREATE DATABASE UserDB;
CREATE DATABASE OtpDB;
CREATE DATABASE AccountDB;
CREATE DATABASE TransactionDB;

Database Configuration

spring.datasource.url=jdbc:postgresql://localhost:5433
spring.datasource.username=neptune
spring.datasource.password=********

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⚙ Prerequisites

• Java 21
• PostgreSQL 16
• RabbitMQ
• Gradle
• RSA Public Key
• RSA Private Key

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🔨 Build Project

cd auth-service
./gradlew build -x test

cd ../user-service
./gradlew build -x test

cd ../otp-service
./gradlew build -x test

cd ../account-service
./gradlew build -x test

cd ../transaction-service
./gradlew build -x test

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▶ Running Services

Start services in the following order:

1. Auth Service
2. OTP Service
3. User Service
4. Account Service
5. Transaction Service

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📚 API Quick Reference

Authentication

POST /auth/login
POST /auth/add-user
GET  /auth/validate

User APIs

POST   /auth/user
GET    /auth/user/{id}
GET    /auth/users
PUT    /auth/user/{id}
DELETE /auth/user/{id}

Account APIs

POST   /api/accounts/create
GET    /api/accounts/get/{id}
GET    /api/accounts/get/all
PUT    /api/accounts/update/{id}
DELETE /api/accounts/delete/{id}

Transaction APIs

POST /transactions/create
POST /transactions/transfer
GET  /transactions/{id}
GET  /transactions/account/{accountId}

OTP APIs

POST /api/otp/send
POST /api/otp/verify

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⚠ Error Response Format

{
  "success": false,
  "message": "Resource not found",
  "errors": [
    "validation message"
  ]
}

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📈 Highlights

✅ Spring Boot Microservices

✅ PostgreSQL Persistence

✅ RabbitMQ Messaging

✅ JWT Authentication

✅ BCrypt Security

✅ OTP Verification

✅ KYC Document Management

✅ Saga-Based Transaction Rollback

✅ Role-Based Access Control

✅ Scalable Architecture

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👨‍💻 Author

Ayshi Shannidhya Panda

GitHub: https://github.com/ayshishannidhya

Email: a.shannidhya@gmail.com

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📜 License

Copyright © 2025-2026 Ayshi Shannidhya Panda.

This project is distributed under a Proprietary License. Unauthorized copying, modification, distribution, or commercial use is prohibited without explicit permission from the author.

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⭐ Neptune Bank

A modern microservices-based banking platform designed for security, scalability, reliability, and enterprise-grade banking operations.