In a recent post to his site Jeroen de Dauw looks at some of his own work and ideas around implementing clean architecture in PHP-based applications. The idea behind "clean architecture" is a focus on separation of concerns and dividing the systems into "layers" with contained logic in each.

Both Domain Driven Design and architectures such as the Clean Architecture and Hexagonal are often talked about. It’s hard to go to a conference on software development and not run into one of these topics. However it can be challenging to find good real-world examples. In this blog post I’ll introduce you to an application following the Clean Architecture and incorporating a lot of DDD patterns. The focus is on the key concepts of the Clean Architecture, and the most important lessons we learned implementing it.

In his post he looks at a real-world application (the Wikimedia Deutschland fundraising software) and how Domain Driven Design plays into the "clean" structure. He then walks through code examples, directory structures and lessons learned along the way (including bounded contexts and effective validation).