Business Capability vs Subdomain Decomposition

There are two common ways to find service boundaries: business capabilities and DDD subdomains.

Capability mapping starts with what the business does. DDD starts with the domain model and the subdomains experts recognize. In many systems, both lead to similar boundaries.

The useful skill is knowing which approach is easier for the situation and spotting where they disagree.

This chapter covers capability mapping, checking boundaries against subdomains, and avoiding technical-layer decomposition.