AI & Technical question

How do you design an API?

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Foundational technical product knowledge, understanding API design principles from a PM's perspective.

Clarify the API's purpose and consumers, internal service to service, or a public third-party developer API, since the bar for stability differs.
Define the core resources and actions, nouns for resources like User or Order, and standard verbs, GET, POST, PUT, DELETE.
Design for consistency and predictability, standard naming conventions, clear error codes, and consistent response formats.
Plan for versioning from the start, e.g. a version prefix in the URL, so changes do not break existing consumers.
Consider rate limiting and authentication, to protect the system and control access for external developers.
Define success criteria, developer adoption ease, measured by time to first successful call, and low support ticket volume for integration issues.

Distinguishes internal versus public APIs, since public APIs need stricter versioning and documentation discipline.
Names concrete design choices, RESTful resource naming and standard HTTP verbs, showing real technical fluency.
Plans for versioning and backward compatibility upfront, not as an afterthought after the first breaking change.
Ties API quality to a measurable developer experience outcome, like time to first successful integration call.

Giving a purely abstract answer with no concrete design choices like naming or versioning.
Ignoring authentication, rate limiting, or error handling considerations.
Not distinguishing internal versus external API design needs.

Chapters of the AI PM course that teach what this question tests.