Service Granularity: Right-Sizing Services

Once service boundaries are clear, the next question is granularity: how large each service should be.

The answer is not based on size alone. Too coarse, and services become mini-monoliths. Too fine, and simple workflows require too many service calls.

A good service owns a complete business capability, and most changes to that capability stay inside it.

This chapter covers cohesion, coupling, signs of services that are too coarse or too fine, and heuristics for finding the right balance.