API-First with OpenAPI 3.2: Design-First Flow, Linting with Spectral, Breaking Change Diffs and Mock Servers
In a design-first flow the OpenAPI contract is a build input: every pull request lints the style guide, looks for breaking changes against the target branch, and checks the freshness of the generated client and drift against the document generated from the code. At Bookstore we see with real output why a Spectral rule never failed, why oasdiff counted a removed parameter as only a warning, the drift check that found the old RPC endpoint, the Prism mock, and Angular types from openapi-typescript.
15 Nov 2026
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14 min
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6
