mock-api-contracts

To validate UI flows before backend implementation, define UI-facing API contracts and test screen interactions against lightweight FastAPI stubs to prove expected responses and error handling.

API contract testing for front-end prototyping defines request, response, and error shapes early to reduce uncertainty between UI design and backend implementation. You need it when validating product discovery assumptions prior to service design.

Generate FastAPI mock endpoints by creating ApiContract artifacts that specify expected request and response shapes, then producing lightweight stubs that simulate endpoint behavior for end-to-end UI validation.

Yes, mock API contracts support front-end driven prototyping by producing a ValidatedAppSlice that demonstrates UI interactions, expected responses, and error cases to validate UX decisions before committing to backend designs.

Contract testing with FastAPI mocks works for validating login and onboarding screens by providing mocked endpoints that confirm UI behavior and error handling prior to actual backend implementation.

Mock API contracts for feature validation are limited to proving UI behavior and validating assumptions against mocked endpoints, meaning they do not replace actual backend service design or handle real data persistence.