Summary
Layering is one of the most used architectural techniques when it comes to designing applications. An application is often split into multiple different layers, each managing a single responsibility. The three most popular layers are presentation, domain, and data. You are not limited to three layers; you can split each into smaller layers (or smaller pieces inside the same conceptual layer), leading to composable, manageable, and maintainable applications.
Moreover, you can create abstraction layers to invert the flow of dependency and separate interfaces from implementations, as we saw in the Abstract layers section. You can persist the domain entities directly or create an independent model for the data layer. You can also use an anemic model (no logic or method) or a rich model (packed with entity-related logic). You can share that model between multiple layers or have each layer possess its own.
Out of layering was born Clean Architecture, which guides the organization...
