schemathesis: Schemathesis - Property-based API Testing for OpenAPI and ...
Schemathesis.io
https://schemathesis.io
As a side note, if you'd like to check what is covered by Schemathesis or any other testing tool or manual tests, you may want to try https://demo.tracecov.sh/ which will generate API coverage reports from many popular formats (there is also a CLI proxy for cases when there is no direct integration)