What are microservices and why are they popular? Should they always be used?

Microservices are an architectural style where an application is broken down into a set of small, independent services, each responsible for its own business function and interacting with others through well-defined APIs.

Why they are popular:

• They allow developing, testing, and deploying services independently.
• They improve scalability — only the parts of the system experiencing load need to be scaled.
• They increase resilience — a failure of one service does not lead to the failure of the entire application.
• They facilitate the use of different technologies and programming languages for different services.

When to use:

• When the project is large and complex enough that dividing into services is beneficial.
• When high scalability and flexibility are required.

When not to use:

• For small or simple applications, microservices can add unnecessary complexity.
• If the team is not prepared for additional complexities in managing a distributed system (e.g., orchestration, monitoring, debugging).

Thus, microservices are a powerful tool, but their implementation should be justified by the project requirements and the team's capabilities.