Rental Management System

I built this to learn the Java microservices stack properly: service discovery, a gateway, asynchronous messaging between services, and what happens when one service is slow or down.

A Spring Cloud gateway sits in front of admin, reporting, and notification services registered with Eureka. Services publish events to RabbitMQ; the notification service turns them into emails and live WebSocket pushes, and the reporting service stores audit history in MongoDB.

1. 01

   Authenticate once, at the edge

   The gateway handles authentication, so the services behind it do not each reimplement token checks.

2. 02

   Events over direct calls for notifications

   Services publish to RabbitMQ instead of calling the notification service directly, so a slow mail server never slows down a user request.

3. 03

   Circuit breakers on cross-service calls

   The reporting service wraps its Feign calls in Resilience4j circuit breakers, so a failing dependency degrades one feature instead of cascading.

• Spring Cloud Gateway with Eureka service discovery
• RabbitMQ events for notifications and audit trails
• Email and STOMP WebSocket push from the notification service
• MongoDB audit and chat history in the reporting service
• Dockerfile per service and a Next.js frontend

• Java
• Spring Boot
• Spring Cloud
• RabbitMQ
• MongoDB
• Next.js