🛡️ Fraud Detection Microservices System

A distributed microservices-based system designed to detect fraudulent transactions in real time.
The system uses event-driven architecture with Kafka, Redis caching, and multiple independent services.

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🏗️ System Architecture

This project follows a microservices architecture where each service has a specific responsibility.

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🚀 Tech Stack

Technology	Purpose
Spring Boot	Backend framework
Spring Security + JWT	Authentication
Apache Kafka	Event streaming between services
Redis	Caching and fast lookups
MySQL	Data storage
Docker & Docker Compose	Containerized deployment
Maven	Dependency management

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📦 Microservices

1️⃣ API Gateway

Handles routing of requests to appropriate microservices.

Port

8080

Responsibilities:

• Request routing
• Entry point for clients

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2️⃣ Auth Service

Handles authentication and authorization.

Port

8081

Features:

• User authentication
• JWT token generation
• User validation

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3️⃣ Transaction Service

Processes financial transactions and publishes transaction events to Kafka.

Port

8082

Features:

• Transaction processing
• Kafka event publishing
• Database persistence

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4️⃣ Fraud Engine Service

Consumes transaction events and runs fraud detection rules.

Port

8083

Features:

• Fraud detection logic
• Risk evaluation
• Event processing

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5️⃣ Notification Service

Sends alerts for suspicious or fraudulent transactions.

Port

8084

Features:

• Fraud alerts
• Notification processing

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🗄️ Database

MySQL is used as the primary database.

Databases Created

auth_db
transaction_db
fraud_db
notification_db

Initialization script:

mysql/init/init.sql

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⚡ Event Flow (Kafka)

Transaction Service
        │
        ▼
   Kafka Topic
        │
        ▼
Fraud Engine Service
        │
        ▼
Notification Service

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🐳 Running the Project

Make sure you have:

• Docker
• Docker Compose
• Java 21

Run the entire system

docker compose up --build

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Check running containers

docker ps

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📊 Services and Ports

Service	Port
API Gateway	8080
Auth Service	8081
Transaction Service	8082
Fraud Engine Service	8083
Notification Service	8084
Kafka	9092
Redis	6379
MySQL	3307

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📂 Project Structure

fraud-detection-microservices
│
├── api-gateway
├── auth-service
├── event-model
├── fraud-engine-service
├── notification-service
├── transaction-service
│
├── mysql
│   └── init
│       └── init.sql
│
└── docker-compose.yml

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🔮 Future Improvements

• Add monitoring with Prometheus + Grafana
• Implement Kafka retry and dead-letter queues
• Add rate limiting at API gateway
• Add distributed tracing (Zipkin)

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👨‍💻 Author

Ravindra Bijarniya

GitHub
https://github.com/Ravindrabijarniya

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💡 If you want, I can also show you **3 small changes that will make this repository look like a FAANG-level backend project (architecture diagram, badges, and API docs)**.