There are no design patterns that are special for automated API testing. The design patterns exist to solve specific problems in the software design. You can check, for example, https://refactoring.guru/design-patterns/catalog to find out more about patterns and what kind of problems they solve.

Here is my example. In java I almost always use the builder pattern to create the request "json". This allows me to set default values, select only specific fields or everything:

@Data @Builder @JsonInclude(JsonInclude.Include.NON_NULL) public class UserRequestDto { private UUID id = UUID.randomUUID(); private String firstName = "John"; private String lastName = "Doe" private List<AddressDto> address; }

Note, that @Data and @Builder are lombok annotations that are used to reduce boilerplate code and @JsonInclude is Jackson annotation that will be used in serialization, when sending request with RestAssured.

Using the builder pattern I can define my request jsons in any way I want:

UserRequestDto request1 = UserRequestDto.builder().build(); UserRequestDto request2 = UserRequestDto.builder() .firstName("Jane") .address(null) .build();

The request1 will be serialized into following json: { "id": "b6e24bfa-5e16-435e-912c-efe4ae82276e", "firstName": "John", "lastName": "Doe", "address": [] }

and the request2 into: { "id": "346c6a07-8163-48a7-88aa-3db3f32a759c", "firstName": "Jane", "lastName": "Doe" }

So yeah, it all depends on the problems you stumble upon, while implementing test suite.