When defining data models for System APIs without an established Enterprise Data Model, MuleSoft recommends mirroring the back-end systems' data types to achieve quick and effective integration without adding complexity. This approach has several benefits:

Alignment with Backend Systems:

Mirroring data types ensures consistency with backend data sources, which simplifies integration, reduces mapping requirements, and minimizes potential data transformation issues.

Flexibility for Future Enhancements:

By retaining close alignment with backend data structures, System APIs can evolve to support an Enterprise Data Model in the future without immediate restructuring.

Explanation of Incorrect Options:

Option A (exposing misspellings) is not recommended as System APIs should still ensure a professional and coherent interface.

Option C (custom naming) complicates the API structure without adding immediate value in the absence of a clear data model.

Option D (exposing all fields) is unnecessary and can reduce performance and add complexity.

ReferencesRefer to MuleSoft best practices for data modeling in System APIs for additional information on mirroring backend systems​.