Schemathesis vs Step CI

Free tier available

Free and open source

Open source. A commercial hosted service exists for reporting and continuous runs.

Free and open source. You pay in engineering time and CI minutes.

The CLI and Python library are open source and free.

Everything, self-hosted

Established

Schemathesis · since 2019

Emerging

Step CI · since 2022

• Enormous coverage for almost no authoring effort — the schema is the test suite.
• Reliably finds unhandled server errors and schema violations that manual tests miss.
• Failures come with a minimal reproducing case.

• YAML workflows are easy to review in a pull request and need no runtime knowledge.
• Generates a starting suite from an OpenAPI spec.
• Includes basic load-testing capability in the same file format.

• Only as good as your schema; a vague or inaccurate spec produces noise.
• Tests conformance, not business correctness — it cannot know a discount was miscalculated.
• Generated failures can be tedious to triage at first.

• YAML hits a ceiling on complex conditional logic.
• Small project with limited community support.
• Ecosystem and reporting are thin compared to established tools.

Any team with an accurate OpenAPI spec who wants deep coverage cheaply.

Small teams wanting declarative, repo-versioned API checks in CI.