Why use DTOs between layers?

DTO (Data Transfer Object) is used for transferring data between layers of an application, for example, between the business logic layer and the presentation layer or between the client and the server.

Main reasons for using DTO:

• Layer isolation: DTO separates internal data models from external representations, allowing internal structures to change without affecting other layers.
• Data transfer optimization: DTO contains only necessary fields, reducing the volume of data transmitted.
• Security: hides sensitive or unnecessary fields that should not be accessible on other layers.
• Simplified serialization: DTOs are often easier to serialize and deserialize because they do not contain complex logic.

Example: In a backend service, there is a complex User model with many fields and relationships, but for client communication, a UserDTO with a limited set of fields (name, email) is used, simplifying and securing data exchange.