contract-testing

Contract testing for HTTP APIs uses the Steps API to verify status codes, header contracts, and response shapes against a live backend. You apply shape-first assertions with typed responses to prevent data leakage and lock the API surface without coupling to UI logic.

To prevent API contract drift across backends, enforce one obligation per test and apply shape-based assertions using reusable schemas. Avoid hardcoding base URLs and rely on provider-aware API calls to maintain deterministic contract verification.

Yes, Playwright supports API contract testing by utilizing the Steps API, which includes apiGet, apiPost, verifyApiStatus, and verifyApiHeader. These steps allow you to assert response schemas and header contracts deterministically.

API contract tests follow a phase-driven workflow from intake through to final reporting. This process ensures each contract obligation is tested separately using provider-aware API calls and typed responses to avoid data leakage into the contract.

You should derive API contracts from an OpenAPI or README spec when available documentation is precise, and use live discovery when specs are absent. Guardrails are applied in both approaches to ensure shape-first assertions and prevent drifting from the intended contract.