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Schemathesis is a modern API testing tool for web applications built with Open API and GraphQL specifications.

It reads the application schema and generates test cases, which will ensure that your application is compliant with its schema.

The application under test could be written in any language; the only thing you need is a valid API schema in a supported format.

Simple to use and yet powerful to uncover hard-to-find errors thanks to the property-based testing approach backed by state-of-the-art Hypothesis library.

Please fill out our quick survey so that we can learn how satisfied you are with Schemathesis, and what improvements we should make. Thank you!


  • Content-Type, schema, and status code conformance checks for Open API;
  • Testing of explicit examples from the input schema;
  • Stateful testing via Open API links;
  • Concurrent test execution;
  • Targeted testing;
  • Storing and replaying network requests;
  • Built-in ASGI / WSGI application support;
  • Ready-to-go Docker image;
  • Configurable with user-defined checks, string formats, hooks, and targets.


To install Schemathesis via pip run the following command:

pip install schemathesis


You can use Schemathesis in the command line:

schemathesis run --stateful=links --checks all

Or in your Python tests:

import schemathesis

schema = schemathesis.from_uri("")

def test_api(case):

CLI is simple to use and requires no coding; the in-code approach gives more flexibility.

Both examples above will run hundreds of requests against the API under test and report all found failures and inconsistencies along with instructions to reproduce them.

See a complete working example project in the /example directory.


Any contribution to development, testing, or any other area is highly appreciated and useful to the project. For guidance on how to contribute to Schemathesis, see the contributing guidelines.

Support this project

Hi, my name is Dmitry! I started this project during my work at I am grateful to them for all the support they provided to this project during its early days and for the opportunity to evolve Schemathesis independently.

In order to grow the community of contributors and users, and allow me to devote more time to this project, please donate today.

Also, I occasionally write posts about Schemathesis in my blog and offer consulting services for businesses.

Commercial support

If you are interested in the effective integration of Schemathesis to your private project, you can schedule an appointment and I will help you do that.


Additional content:


The code in this project is licensed under MIT license. By contributing to Schemathesis, you agree that your contributions will be licensed under its MIT license.