Onion architecture compared to hexagonal

Question

Is there any difference between them (onion | hexagonal), from my understanding they are just the same, they focus upon the domain which is at the core of the application and sh

Answer 1

There is a difference between the layered architecture and the onion related family of architectures. The layered architecture works with a hierarchical relationship between the user interface and the data access layers. In contrast, the onion architecture considers UI and data access to be part of the same layer.

How come user interface and data access are on the same layer? At the core of the onion architecture lies the domain with its business logic. This is the primary focus. The domain isn't above or below any other layer. It is the very center. User interfaces, rest endpoints and the like are secondary to the domain, just as data repositories.

The ports and adapters architecture (which is another name for the hexagonal architecture) makes this clear by its name: There are any number of ports that act as interfaces between the domain and the outside. Adapters implement the ports so that the ports can interact with the domain.

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EDIT: I understand that the wording that "the onion architecture considers UI and data access to be part of the same layer" can be interpreted in a different way than was intended. The point is that in the onion architecture, the user interface and data access functionality are not in a hierarchical relationship, as is the case in the layered architecture.