RequestDTO

RequestDTO (data transfer object) is a type used to carry input data for a service call or API request. It acts as a boundary between external clients and internal systems, encapsulating the parameters sent by a client and decoupling them from domain models.

Design goals include simplicity, serializability, and validation. A RequestDTO typically contains fields such as pagination (page, size), filters, sorting, search terms, and optional metadata. It usually avoids business logic and domain methods; validation rules may be applied via annotations or schemas.

Usage pattern involves the web layer binding incoming data to a RequestDTO, validating it, and mapping it to a service-level request or domain command. A mapping layer converts between RequestDTO and internal models. The service processes the request and returns a ResponseDTO or other result.

Variants and considerations include versioning of RequestDTOs to support API evolution, and the potential need to evolve fields without breaking clients. Reusing a single DTO across endpoints may require careful design. It is important to separate concerns for security-related aspects and to avoid including authentication or authorization logic in the DTO itself; such concerns are typically handled at a different layer.

In practice, RequestDTOs are part of layered architectures and API design, supporting cleaner controllers, easier testing, and clearer boundaries between client input, validation, and business logic.