Decomposition Anti-Patterns

Breaking a large application into microservices sounds straightforward. Identify the major features, create separate services, and let them communicate through APIs or events.

But in practice, choosing the wrong service boundaries can make a system significantly harder to develop, deploy, and maintain. An application that previously worked as a single process may now require dozens of network calls, distributed transactions, and coordinated deployments just to complete a simple operation.

This happens because splitting an application into smaller services does not automatically make those services independent. Poor decomposition can introduce tight coupling, unclear ownership, and unnecessary operational complexity. These recurring design mistakes are called decomposition anti-patterns.

In this chapter, we'll explore the most common anti-patterns, understand why they cause problems, and discuss how to recognize and avoid them in real-world microservices architectures.