Welcome to Schemathesis!

Schemathesis is a tool that levels-up your API testing by leveraging API specs as a blueprints for generating test cases. It focuses on testing for general properties — such as ensuring no input leads to server errors and all responses adhere to the API spec — rather than just checking specific input-output combinations.

This approach broadens your testing suite’s capability to detect a wide range of potential issues, from trivial bugs to critical vulnerabilities.

🎯 Catch Hard-to-Find Bugs

  • Uncover hidden crashes and edge cases that manual testing might miss

  • Identify spec violations and ensure your API adheres to its contract

⚡ Accelerate Testing Cycles

  • Automatically generate a wide range of test cases based on your API schema

  • Save time by reducing the need for manual test case creation

🧩 Integrate Seamlessly

  • Works with popular API formats such as OpenAPI, GraphQL.

  • Easily integrate into your existing CI/CD workflows.

🔧 Customize and Extend

  • Tune the testing process using Python extensions.

  • Adjust the testing flow to suit your needs with rich configuration options.

🐞 Simplifies Debugging

  • Get detailed reports to identify and fix issues quickly.

  • Reproduce failing test cases with cURL commands.

🔬 Proven by Research

  • Validated through academic studies on API testing automation

  • Featured in ICSE 2022 paper on semantics-aware fuzzing

  • Recognized in ACM survey as state-of-the-art RESTful API testing tool

How it works?

Here’s an overview of how Schemathesis works:

  1. Test Generation: Using the API schema to create a test generator that you can fine-tune to your requirements.

  2. Execution and Adaptation: Sending tests to the API and adapting through statistical models and heuristics to optimize test cases based on responses.

  3. Analysis and Minimization: Checking responses for issues and simplifying failing test cases for easier debugging.

  4. Stateful Testing: Running multi-step tests to assess API operations in both isolated and integrated scenarios.

  5. Reporting: Generating detailed reports with insights and cURL commands for easy issue reproduction.

Research Findings on Open-Source API Testing Tools

Our study, presented at the 44th International Conference on Software Engineering, highlighted Schemathesis’s performance:

  • Defect Detection: identified a total of 755 bugs in 16 services, finding between 1.4× to 4.5× more defects than the second-best tool in each case.

  • High Reliability: consistently operates seamlessly on any project, ensuring unwavering stability and reliability.

Explore the full paper at IEEEXplore or pre-print at arXiv.

Community & Support

Join our Discord channel for access to learning resources and prompt support to resolve questions and expand your knowledge.

If you’re a large enterprise or startup seeking specialized assistance, we offer commercial support to help you integrate Schemathesis effectively into your workflows. This includes:

  • Quicker response time for your queries.

  • Direct consultation to work closely with your API specification, optimizing the Schemathesis setup for your specific needs.

To discuss a custom support arrangement that best suits your organization, please contact our support team at support@schemathesis.io.

User’s Guide

The User Guide explains different parts of Schemathesis and how they can be used, customized, and extended. It generally follows the operational workflow of Schemathesis, detailing steps from initial schema loading to test generation, execution, and result evaluation.