What exactly did you do when designing the API — what was your responsibility?

When designing APIs, my responsibilities typically included:

• Analyzing requirements and understanding the business logic that the API should support.
• Defining the structure of endpoints, methods (GET, POST, PUT, DELETE), and data formats (JSON, XML).
• Designing data schemas and models to be used in the API.
• Ensuring API security: authentication, authorization, protection against attacks.
• Documenting the API (e.g., using OpenAPI/Swagger) for ease of use by other developers.
• Collaborating with the development and testing teams to clarify details and support implementation.

Thus, I was responsible for making sure the API was understandable, user-friendly, secure, and met the project requirements.