This layer contains all the user interfaces of an application. In terms of ASP.NET Core, it contains MVC controllers, views, static files (images, HTML pages), JavaScript files, and other client-side frameworks like Angular, Knockout, and others. This is the frontend layer with which the user interacts. Keeping this layer separate facilitates upgrading the existing interfaces or design without making any changes to the backend layers.

There are some architectural principles which should be followed when designing the presentation layer. A good presentation layer design can be achieved by following these three principles:

• First of all, our data should be separated from view and use patterns like MVC, MVVM, or MVP to address separation of concerns.
• Separate teams should work on the UI and business layer simultaneously.
• Minimize the application logic separate from the presentation layer -- the presentation layer should only contains forms, fields, validation, and related checks. All server-side logic should reside on the business layer.