Api Design and Versioning
Design and evolve application programming interfaces so they meet functional requirements while minimizing disruption to clients and services. Core skills include designing resource oriented endpoints, choosing and implementing versioning strategies, and preserving backward compatibility. Candidates should understand versioning approaches such as embedding a version in the endpoint path, using request headers to select versions, and designing non breaking changes so explicit version bumps are avoided. Important topics include idempotency, pagination, filtering, sorting, error response design, status semantics, rate limiting, authentication and authorization, and considerations for low bandwidth or mobile clients. At senior levels discuss operational and lifecycle concerns: deprecation policies and timelines, migration plans, compatibility testing, handling multiple client versions simultaneously in production, rolling deployments and coexistence strategies, contract testing, and alternatives such as remote procedure call frameworks. Expect trade off discussions around developer experience, client upgrade friction, monitoring and instrumentation for versioned traffic, and communication strategies with downstream consumers.
