Application Programming Interface Testing Fundamentals Questions

Covers testing of programmatic interfaces between systems. Candidates should demonstrate how to design and execute interface tests that verify correct behavior and resilience of endpoints, including request and response patterns, common request methods such as get post put patch and delete, response status code semantics and error handling, request and response payload validation against schema definitions, contract testing and interface specification validation, authentication and authorization enforcement, and idempotency and retry semantics. Also include negative testing and boundary conditions, concurrency and transactional integrity, pagination and sorting validation, and data consistency checks. Assess security testing for injection style attacks and improper authorization, performance and rate limiting under load, mocking and stubbing of external dependencies, test data management and environment isolation, integration of interface tests into automated pipelines and continuous integration, observability and logging for troubleshooting, and best practices for prioritizing interface tests versus end to end user interface tests.