contract-testing

Contract testing replaces slow end-to-end tests by having consumers define API expectations and providers verify them independently. This approach isolates integration failures early without deploying the entire microservices stack.

Pact provider verification works by replaying consumer contract interactions against the provider API. State handlers configure the necessary provider state before each interaction is verified, ensuring the API meets the defined contract expectations.

Yes, OpenAPI or Zod middleware enforces API contracts at runtime by validating requests and responses against the defined schema. This detects breaking API changes proactively at the API boundary.

Consumer-driven contract testing is a method where API consumers define their expected interactions, and providers verify they meet those expectations. You need it in microservices architectures to prevent deployment-related integration failures.

Yes, contract testing detects breaking API changes by verifying consumer contracts against the provider. If a provider modifies an endpoint in a way that violates a consumer contract, the verification fails before deployment impacts consumers.

Contract testing provides integration assurance without requiring full end-to-end tests. While it ensures microservices integrate correctly by verifying contracts, you may still use end-to-end tests sparingly for critical user journeys across the entire stack.