ONION-ARCHITECTURE

Concentric layers, inward dependency.

Definition

Onion: Domain Model (center), Domain Services, Application Services, Infrastructure (outermost). All dependencies point inward. Repository interfaces defined in Domain, implemented in Infrastructure. Influences DDD (Eric Evans 2003).

Origin

Published by Jeffrey Palermo July 2008 in a 4-article series.

Example in context

A .NET EDI app applies Onion: Core (Invoice, Order entities), Domain Services (validation), Application (orchestration), Infrastructure (EF Core, AS2 adapter).

Related terms

• Hexagonal — predecessor.