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Microservices

Topics

  • 1. What are Microservices?
  • 2. Microservices vs Monolithic Architecture 
  • 3. Advantages of Microservices
  • 4. Disadvantages of Microservices
  • 5. When NOT to Use Microservices
  • 6. What is Service Decomposition?
  • 7. How Do Microservices Communicate?
  • 8. What is Bounded Context?
  • 9. What is Domain-Driven Design (DDD)?
  • 10. Stateless vs Stateful Services
  • 11. How Do You Design Microservices?
  • 12. How Do You Decide Service Boundaries?
  • 13. What is an API Gateway?
  • 14. Benefits of API Gateway
  • 15. API Gateway vs Load Balancer
1. What are Microservices?

  • Microservices are an architectural style where software is built as a collection of small, independent services, each focused on a single function.

  • Key points:

    • Each service runs independently.

    • Developed and deployed separately.

    • Communicate through APIs (Application Programming Interfaces).

Example (Online Shopping App):

  • User Service: Manages user accounts.

  • Product Service: Handles product catalog.

  • Payment Service: Processes payments.

  • Each service can be updated or scaled without affecting the others.

2. Microservices vs Monolithic Architecture 

Feature Monolithic Microservices
Structure Single large application Many small independent services
Deployment Entire app deployed at once Each service deployed independently
Scalability Scale whole app Scale individual services
Failure impact One bug can crash everything Bug usually affects only one service
Development Harder for multiple teams Easier for multiple teams
Technology Usually one tech stack Each service can use different tech

In short:

  • Monolithic: One big block of code.

  • Microservices: Many small blocks working together.

3. Advantages of Microservices

    1. Scalability: Only the services that need more resources are scaled, saving cost and improving performance.

    2. Independent Deployment: Services can be updated or deployed without affecting the entire application.

    3. Flexibility in Technology: Each service can use the best-suited programming language, framework, or database.

    4. Fault Isolation: Failures in one service usually don’t crash the whole system.

    5. Better Team Organization: Teams can own specific services, reducing conflicts and improving efficiency.

4. Disadvantages of Microservices

  • Complexity: Managing multiple services is more complicated than a single application.

  • Network Latency: Communication between services over APIs can be slower than internal calls in a monolith.

  • Data Management Challenges: Maintaining consistency across distributed services is harder.

  • Monitoring & Debugging Difficulty: Tracing issues across multiple services can be challenging.

  • DevOps Overhead: Requires robust CI/CD pipelines, deployment automation, and monitoring tools.

5. When NOT to Use Microservices

Microservices may not be suitable if:

  • The application is small or simple — a monolithic approach is faster and easier.

  • The team is small or lacks DevOps expertise.

  • There’s little need for independent scaling or deployment.

  • You want simpler data management — microservices often need distributed databases.