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. This architecture is not appropriate for small websites. It is appropriate for long-lived business applications as well as applications with complex behavior. It emphasizes the use of interfaces for behavior contracts, and it forces the externalization of infrastructure.
jeffreypalermo.com/blog/the-onion-architecture-part-1/