API Design and Frontend Integration Questions

Design APIs that frontend applications can reliably consume. Cover resource modeling, HTTP method semantics, status codes and error payloads, response shape and field selection, pagination and filtering strategies, and approaches for minimizing bandwidth. Discuss versioning and backward compatibility, idempotency, authentication and authorization, rate limiting, and caching headers. Explain contract first design, documentation and contract testing, and tradeoffs between HTTP resource oriented designs and alternative approaches. Provide concrete endpoint examples and describe how to make API choices that simplify frontend integration and evolution.