API Testing: From Postman Collections to Contract Tests in CI

Consumer-driven contracts verify that provider changes don't break real client expectations — the mechanical answer to 'who broke the integration.'

Seeded test data, cleanup discipline, and explicit tests that retries don't duplicate effects — the idempotency promise deserves proof.

Skipping the discipline this article describes until an incident, audit, or stalled project forces it — every practice above is cheaper adopted early than retrofitted under pressure.