Microservices Architecture

Definition

Microservices Architecture is a design approach where an application is built as a collection of small, independent services that communicate through well-defined APIs. Each service is self-contained, focuses on a specific business capability, and can be developed, deployed, and scaled independently.

When to Use It

You need to scale different parts of your application independently
Your team is large and can work on multiple services simultaneously
You want to use different technologies for different services
You need to deploy and update parts of the system independently
Your application has distinct business domains that can be separated
You require high availability and fault isolation

Pros & Cons

✓ Pros

Independent scaling of services
Technology diversity and flexibility
Faster deployment cycles
Better fault isolation
Easier to understand and maintain small services
Team autonomy and parallel development

✗ Cons

Increased operational complexity
Network latency and reliability concerns
Distributed system challenges (data consistency)
Testing becomes more complex
Requires sophisticated DevOps practices
Higher infrastructure costs initially

Architecture Diagram

┌─────────────────────────────────────────────────────────────────┐
│                         API Gateway                             │
│                      (Entry Point)                              │
└────────────┬────────────┬────────────┬────────────┬─────────────┘
             │            │            │            │
             ▼            ▼            ▼            ▼
      ┌──────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐
      │  User    │ │ Product  │ │ Order    │ │ Payment  │
      │ Service  │ │ Service  │ │ Service  │ │ Service  │
      └────┬─────┘ └────┬─────┘ └────┬─────┘ └────┬─────┘
           │            │            │            │
           ▼            ▼            ▼            ▼
      ┌─────────┐ ┌─────────┐ ┌─────────┐ ┌─────────┐
      │  User   │ │ Product │ │  Order  │ │ Payment │
      │   DB    │ │   DB    │ │   DB    │ │   DB    │
      └─────────┘ └─────────┘ └─────────┘ └─────────┘
           │            │            │            │
           └────────────┴────────────┴────────────┘
                           │
                           ▼
                  ┌────────────────┐
                  │ Message Queue  │
                  │  (Event Bus)   │
                  └────────────────┘

Key Components:
• Each service has its own database (Database per Service)
• Services communicate via APIs or message queues
• API Gateway routes requests to appropriate services
• Independent deployment and scaling per service