Application Programming Interface Design Questions

Designing application programming interfaces for enterprise integration involves creating clear, stable contracts and integration patterns that support security, scale, and maintainability. Candidates should be able to discuss endpoint design and representation styles such as representational state transfer or remote procedure call frameworks, authentication and authorization approaches including token based flows and single sign on, and how to protect data in transit and at rest. Important considerations include pagination and bulk patterns, rate limiting and back pressure, idempotency and retry semantics, error models and consistent error codes, versioning and deprecation strategies to preserve backward compatibility, and schema evolution for request and response payloads. At enterprise scale evaluate performance and scaling strategies such as stateless service design, caching, horizontal scaling of the gateway and application tiers, and the use of an intermediary gateway for routing, authentication, and observability. Integration patterns should cover synchronous request response as well as asynchronous callbacks and event driven approaches where appropriate, and explain how to correlate requests across distributed components with correlation identifiers and tracing. Finally demonstrate attention to developer experience with clear documentation and example clients, testing strategies including sandbox and staging environments, monitoring and alerting for latency and error rates, and operational plans for rollout, version migration, and support.