https://github.com/cebe/yii2-openapi/issues/3 > According to the OAS 3 Spec, status codes that are available are defined in > https://tools.ietf.org/html/rfc7231#section-6 > > The generated code is returning 422 for example. > https://github.com/OAI/OpenAPI-Specification/blob/3.0.2/versions/3.0.2.md#httpCodes > > These code is not defined in the RFC. > If i am correct it should return 400 instead. > > Or for duplicate errors: 409