To separate technical from domain code, architectural approaches like Hexagonal or Onion Architecture are currently all the rage. However, discussions about their semantic details and their mapping to the source code structure of software projects are at least equally ubiquitous.

How much abstraction and mapping between architectural concepts is needed? Is persistence metadata in the domain model heresy? Above all: what is the actual goal of the exercise, and: does it have to be so complicated?

We address these and other questions in a theoretical overview and by looking at concrete examples. We discuss the trade-offs of different approaches and how various tools and libraries help us to maintain the intended structure.

Alternative title: “Technical decomposition – You’re doing it wrong!”