Designing an API involves a critical decision in choosing between a resource-first or a workflow-first approach, each having distinct implications for the API's design. The resource-first method begins with modeling domain entities as resources and implementing standard CRUD operations, offering predictability and alignment with REST principles, but it may lead to inefficiencies such as multiple calls for workflows and exposure of internal data structures. Alternatively, the workflow-first approach focuses on user needs by designing endpoints around key use cases, optimizing for usability and performance, though it requires a thorough understanding of the domain and can result in less predictable, RPC-style APIs. The most effective APIs often blend both approaches, starting with workflow considerations and validating with resources, thereby supporting efficient user workflows while maintaining a clear, resource-based structure. This hybrid approach allows for flexibility, catering to both complex workflows and simple operations, ensuring that the API is both intuitive for users and easy to evolve over time.