Hackforge Academy

Explanation

As applications grow, a single monolithic application can become difficult to maintain, deploy, and scale. Microservices solve this by breaking a large application into smaller, independent services.

Code:

MONOLITH

┌─────────────────────────────┐
│ User │ Order │ Payment │ Product │
└─────────────────────────────┘

        ↓ Microservices

User Service | Order Service | Payment Service | Product Service

Explanation

Microservices allow teams to develop and deploy individual business functionalities independently. A change in one service does not require deploying the entire application.

Code:

MONOLITH

Change Payment Service
        ↓
Build + Test + Deploy Everything

MICROSERVICES

Change Payment Service
        ↓
Deploy Payment Service Only

Explanation

Each microservice can be scaled independently based on traffic. If the Order Service receives more requests, additional Order Service instances can be created without scaling the other services.

Code:

High Traffic
     ↓
Order Service
     ↓
┌──────────┬──────────┬──────────┐
│ Instance │ Instance │ Instance │
│    1     │    2     │    3     │
└──────────┴──────────┴──────────┘

User Service → 1 instance

Explanation

Microservices provide fault isolation. If one service has a problem, other services can continue running. Patterns such as Circuit Breaker and Retry can help handle failures.

Code:

Order Service
      ↓
Payment Service ❌
      ↓
Circuit Breaker
      ↓
Fallback Response

User Service → Working ✓
Product Service → Working ✓

Explanation

Different services can use technologies that best fit their requirements. For example, Java and Spring Boot can be used for business services, while Python can be used for an AI or data-processing service.

Code:

User Service       → Java + Spring Boot
Order Service      → Java + Spring Boot
Payment Service    → Java + Spring Boot
AI Service         → Python + FastAPI
Notification       → Node.js

Explanation

Microservices are useful for large and complex applications that need independent deployment, scaling, team ownership, and fault isolation. However, they also introduce complexity such as network communication, monitoring, security, and distributed transactions.

Code:

MICROSERVICES
      ↓
Independent Deployment
Independent Scaling
Fault Isolation
Team Independence
Technology Flexibility

BUT
      ↓
More Distributed-System Complexity