Defining API personas is a crucial step in designing and developing APIs (Pedro 2023). API personas help programs understand the needs, preferences, and behaviors of target users and consumers. Personas ensure developers are creating APIs that meet their specific requirements and testing and validating API functionality across each persona’s use cases.—Application Programming Interface (API) Technical Guidance, Office of the Under Secretary of Defense for Research and Engineering, April 2025

I accidentally found this 120-page report about API Technical Guidance (PDF), published by the U.S. Under Secretary of Defense for Research and Engineering in April 2025. It cites me on content related to API design.