Job Application Platform – Microservices Architecture

A backend Job Application Platform built using Spring Boot Microservices, demonstrating how a monolithic system can be decomposed into independently deployable services with synchronous inter-service communication.

This project focuses on service design, communication, observability, containerization, and scalability concepts used in real-world backend systems.

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🧩 Microservices Overview

The application is split into the following services:

• Job Service

  • Manages job listings
  • CRUD operations for jobs
  • Acts as the primary service for job-related APIs

• Company Service

  • Manages company information
  • Maintains relationship between companies and jobs

• Review Service

  • Manages reviews for companies
  • Linked with company service

• Service Registry (Eureka)

  • Enables service discovery
  • Allows services to communicate using service names

• API Gateway

  • Basic setup completed
  • Advanced routing, resilience & rate limiting planned (WIP)

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🔁 Inter-Service Communication

• Synchronous communication implemented using:
  • RestTemplate
  • OpenFeign Clients
• Service-to-service calls via Eureka service discovery
• DTO pattern used to avoid tight coupling between services

Example:

• Job Service fetching company & review details
• Aggregated job response using DTOs

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🗄️ Data & Persistence

• Each microservice owns its own database schema
• PostgreSQL used as the primary database
• Spring Data JPA & Hibernate
• Entity relationships handled within service boundaries

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🐳 Docker & Containerization

• Each microservice is containerized using Docker
• Multi-container setup using Docker Compose
• PostgreSQL runs as a separate container
• Docker networks used for inter-container communication

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📊 Observability & Monitoring

• Spring Boot Actuator
  • Health
  • Metrics
  • Info
  • Logs
• Distributed Tracing
  • Zipkin integrated via Micrometer
  • Trace IDs propagated across services
  • End-to-end request visibility

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🧠 Key Concepts Implemented

• Monolith → Microservices refactoring
• Service Discovery (Eureka)
• Inter-service communication
• DTO pattern
• Containerized microservices
• Distributed tracing
• Actuator-based monitoring
• Clean service boundaries

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🚧 Work in Progress (Planned Next)

The following features are intentionally planned and will be implemented next:

• Advanced API Gateway routing
• Load-balanced routing via Gateway
• Fault tolerance using Resilience4j
  • Circuit Breaker
  • Retry
  • Rate Limiting
  • Fallback mechanisms
• Configuration Management using Spring Cloud Config
• Centralized configuration repository

These enhancements are planned as part of incremental system hardening.

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🏗️ Tech Stack

• Java 21
• Spring Boot
• Spring Cloud
• Eureka Service Registry
• Spring Cloud Gateway
• OpenFeign
• Spring Data JPA
• PostgreSQL
• Docker & Docker Compose
• Zipkin + Micrometer
• Maven

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🎯 What This Project Demonstrates

✔ Real-world microservices design
✔ Clear service boundaries
✔ Synchronous communication patterns
✔ Observability & tracing
✔ Container-first mindset
✔ Incremental system evolution

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👤 Author

Nihal Singh
Backend Developer | Java | Spring Boot | Microservices

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This project reflects an evolving microservices system, built step-by-step following industry best practices.