Schemathesis
Schemathesis automatically generates property-based tests from your OpenAPI or GraphQL schema, chains operations into realistic workflows, and exercises the edge cases that break your API.
Finding a server error that manual testing missed
Supported specifications
| Specification | Versions |
|---|---|
| OpenAPI | 2.0 (Swagger), 3.0, 3.1, 3.2 |
| GraphQL | June 2018 and later |
| gRPC | Unary methods, see the gRPC guide |
Why teams choose Schemathesis
- 🎯 Catches server errors, schema violations, and validation gaps that hand-written tests miss.
- 🧠 Adapts as it runs: learns from server responses, threads real values into later requests, and shifts effort away from operations that aren't producing useful signal.
- 🔄 Tests multi-step workflows, not single requests in isolation: follows OpenAPI
links, infers relationships where they aren't declared, and carries real identifiers between operations. - ⏱️ No per-endpoint tests to maintain — point it at your schema and run.
- 🐛 Every finding ships with a minimal
curlreproducer. - 🔌 Plugs into existing setups: CLI,
pytest, GitHub Actions, plus Allure, JUnit XML, and HAR output.
Developer feedback
"The tool is amazing as it can test negative scenarios instead of me and much faster!"
— Luděk Nový, JetBrains
Documentation
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New to Schemathesis?
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How-To Guides
Practical guides for common scenarios:
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Want to understand how it works?
Deep dive into concepts:
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Need technical details?
Complete reference:
Important
Upgrading from older versions? See the Migration Guide for key changes.