Response Validation

Response validation checks handler output against the @Returns schema for the final status code.

Enable Globally

const app = createApp({
    schema: classValidator(),
    controllers: [ReportsController],
    validateResponse: true,
});

@Get("/summary")
@Returns(200, SummaryDto, "Summary payload")
summary() {
  return { total: 10 };
}

Method-level setting overrides controller-level setting, which overrides global createApp config.

Validation mismatch is treated as a server error and flows through errorFormatter.