NexusPay - Advanced Event-Driven Microservices Wallet System

NexusPay is a high-performance, event-driven digital wallet ecosystem designed for scalable financial transactions. It leverages Apache Kafka for asynchronous inter-service communication and is fully orchestrated using Kubernetes (K8s) to ensure high availability and fault tolerance.

🔗 Local Cluster Access: http://localhost:8080

(Note: Access requires Port-Forwarding the Gateway Service within your K8s cluster)

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🚀 Key Features

💰 Core Wallet & Ledger

• Real-Time Transaction Processing: Instant balance updates and transaction logging triggered by system events.
• Event-Driven Architecture: Asynchronous communication between services using Kafka Topics (user-created-topic, wallet-transactions).
• High-Speed Caching: Optimized transaction history retrieval using Redis with RedisSerializer.json() for efficient data handling.
• Transaction History: Detailed logs for DEPOSIT and WITHDRAW operations with unique transaction IDs.

🛠 Infrastructure Excellence (Engineering Highlight)

• Kubernetes Orchestration: Fully containerized services managed via K8s Deployments and Services for seamless scaling.
• Kafka Listener Optimization: Resolved complex PLAINTEXT_INTERNAL protocol mappings to ensure stable broker-client connectivity.
• Database Reliability: Robust PostgreSQL integration with Spring Data JPA, featuring secure credential management and dialect optimization.
• API Gateway: Centralized routing and request filtering through Spring Cloud Gateway.

🔒 Security & Performance

• JWT Authentication: Secure user sessions managed by the Auth Service.
• Modern Serialization: Custom RedisTemplate configuration using StringRedisSerializer for keys and JSON serializers for values.
• Resilience: Automatic pod recovery and "CrashLoopBackOff" troubleshooting strategies implemented for high uptime.

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🏗 Tech Stack

Backend Services

• Language: Java 17
• Framework: Spring Boot 3.x
• Messaging: Apache Kafka (Distributed Event Streaming)
• Caching: Redis (Data Persistence & Speed)
• Database: PostgreSQL (Relational Data)
• Build Tool: Maven

DevOps & Orchestration

• Containerization: Docker & Docker Compose
• Orchestration: Kubernetes (K8s)
• Networking: Spring Cloud Gateway
• API Testing: Postman

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⚙️ Installation & Setup (Local K8s)

Prerequisites

• Docker Desktop (K8s Enabled)
• Java JDK 17+
• Maven
• Kubectl

Steps to Run

1. Start Infrastructure: Run docker-compose up -d and verify Kafka is running.
2. Build and Push:

mvn clean package -DskipTests
docker build -t your-username/wallet-service:latest ./wallet-service
docker push your-username/wallet-service:latest

Clone the Repository

git clone https://github.com/yigitkagankartal/Realtime-chat.git