ORGANIZE YOUR APPLICATIONS

What is Onion Architecture?

Onion Architecture is a method for organizing applications to manage dependencies, simplify the structure, and stand as a defense to technical debt. For over a decade, developers around the world have used Onion Architecture to empower their development teams.

First published in 2008 by Jeffrey Palermo, Onion Architecture has grown in popularity with others citing it as a reference for other works:

• Robert Martin’s Clean Architecture
• ASP.NET MVC in Action
• .NET DevOps for Azure
• Microsoft TechNet articles

SIMPLIFY THE STRUCTURE

Why Onion Architecture?

Jeffrey writes:

I’ve spoken several times about a specific type of architecture I call Onion Architecture. I’ve found that it leads to more maintainable applications since it emphasizes separation of concerns throughout the system. I must set the context for the use of this architecture before proceeding.

The diagram you see here is a representation of traditional layered architecture. This is the basic architecture I see most frequently used. Each subsequent layer depends on the layers beneath it, and then every layer normally will depend on some common infrastructure and utility services.

The big drawback to this top-down layered architecture is the coupling that it creates. Each layer is coupled to the layers below it, and each layer is often coupled to various infrastructure concerns. However, without coupling, our systems wouldn’t do anything useful, but this architecture creates unnecessary coupling.

Read more here: The Onion Architecture