Microservices promise independent deployment and independent scaling. They also introduce network calls, partial failures, and distributed data. Whether the trade is worth it depends almost entirely on where the boundaries are drawn.
Draw boundaries around data
A good service owns its data and exposes behaviour, not tables. If two services need to write the same records, they are probably one service. Boundaries drawn around business capabilities tend to survive longer than those drawn around technical layers.
Communication style matters as much as boundaries. Synchronous calls are simple to reason about but couple availability together. Asynchronous messaging decouples services in time, at the cost of eventual consistency.
Every network call you add is a failure mode you have to design for.
Scale the bottleneck, not the diagram
Measure before splitting. In many systems a single component carries most of the load, and scaling that component alone is enough. Splitting everything else adds operational overhead without changing throughput.
- Give every service its own health check and dashboards.
- Set timeouts and retries deliberately, with backoff.
- Version APIs so consumers can upgrade on their own schedule.
A well-structured modular monolith is often the right starting point. Clean module boundaries make a later split straightforward, while premature services make every change a coordination exercise.