YAML based api testing and API microbenchmarking tool in Python


PyRestTest is an open-source API testing and automation tool designed to be simple, lightweight, and extensible. It allows developers and QA engineers to test RESTful APIs by writing tests in YAML or JSON, making it accessible even for those with minimal programming experience. PyRestTest focuses on providing a straightforward way to create and run tests, verify responses, and automate the testing process, ensuring that APIs function correctly and meet specified requirements. Its simplicity, combined with its powerful features, makes PyRestTest a valuable tool for both development and continuous integration workflows.


PyRestTest offers a range of features that cater to various API testing needs:

  1. YAML/JSON-Based Test Definitions: Tests are defined in easy-to-read YAML or JSON formats, allowing for clear and maintainable test configurations.
  2. Support for RESTful APIs: PyRestTest is specifically designed for testing RESTful APIs, supporting standard HTTP methods such as GET, POST, PUT, DELETE, and PATCH.
  3. Assertions and Validations: The tool includes a comprehensive set of assertions to validate API responses, including status codes, headers, and response bodies.
  4. Data-Driven Testing: PyRestTest supports parameterization and data-driven testing, allowing the same test to be executed with different sets of data.
  5. Setup and Teardown: Users can define setup and teardown actions to prepare the environment before tests run and clean up afterward, ensuring a consistent testing state.
  6. HTTP Authentication: The tool supports various authentication methods, including Basic Auth and Token-based authentication, to test secured endpoints.
  7. Response Timing and Performance Metrics: PyRestTest can measure and report response times, helping to identify performance issues.
  8. Extensible with Python Hooks: For advanced users, PyRestTest provides hooks to extend functionality with custom Python code, enabling more complex testing scenarios.
  9. Command-Line Interface: The tool can be run from the command line, making it easy to integrate into CI/CD pipelines and automated testing workflows.
  10. Detailed Reporting: Test results are provided in a detailed and readable format, making it easy to identify and diagnose failures.


PyRestTest has several advantages that make it a preferred choice for many API testing scenarios:

  1. Simplicity and Ease of Use: The YAML/JSON-based configuration allows users to define tests without needing deep programming knowledge, making it accessible to a broader audience.
  2. Lightweight and Fast: PyRestTest is a lightweight tool with minimal dependencies, ensuring quick setup and execution of tests.
  3. Open Source and Free: As an open-source project, PyRestTest is free to use and can be modified to suit specific needs, providing flexibility and cost savings.
  4. Extensible: The ability to extend functionality with Python hooks allows advanced users to tailor the tool to complex testing requirements.
  5. Comprehensive Assertions: A wide range of built-in assertions ensures thorough validation of API responses, enhancing test coverage.
  6. Integration with CI/CD Pipelines: The command-line interface and ease of automation make PyRestTest suitable for continuous integration and deployment workflows.
  7. Community Support: Being an open-source tool, PyRestTest has a community of users and contributors who can provide support, share insights, and collaborate on improvements.


Despite its strengths, PyRestTest has some limitations:

  1. Limited Advanced Features: Compared to more comprehensive API testing tools, PyRestTest lacks some advanced features such as graphical user interface (GUI), extensive reporting, and built-in integrations with popular development tools.
  2. Performance with Large Test Suites: PyRestTest may experience performance issues when handling very large test suites or complex testing scenarios, which can impact execution times.
  3. Documentation and Community Size: While there is community support, the documentation and size of the user community are not as extensive as those of more popular tools, which can make troubleshooting and learning more challenging.
  4. No Built-In Load Testing: PyRestTest does not support load testing out of the box, limiting its use for performance testing and stress testing of APIs.
  5. Dependency on External Libraries: Some functionalities may require additional Python libraries, which can complicate setup and increase dependencies.

Using PyRestTest to automate API testing is straightforward. Here’s an example of how to set up and run a basic test.


sh pip install pyresttest

Creating a Test File (example.yaml):

- config:
    testset: "Example API Tests"

- test:
    - name: "Get Users"
      url: ""
      method: "GET"
      expected_status: [200]
        - compare:
            jsonpath: "length($)"
            operator: "eq"
            expected: 10

    - name: "Create User"
      url: ""
      method: "POST"
      body: '{"name": "John Doe", "email": ""}'
        Content-Type: "application/json"
      expected_status: [201]
        - compare:
            jsonpath: "$.name"
            operator: "eq"
            expected: "John Doe"

Running the Test:

sh pyresttest example.yaml



PyRestTest is an open-source tool released under the Apache 2.0 license, making it free to use for both personal and commercial projects. There are no licensing fees or subscription costs associated with PyRestTest, which makes it an attractive option for budget-conscious teams and organizations.

PyRestTest is recommended for:

  1. Individual Developers and Small Teams: Its simplicity and ease of use make it ideal for individual developers and small teams who need a straightforward solution for API testing.
  2. Budget-Conscious Projects: As a free and open-source tool, PyRestTest is suitable for projects with limited budgets that still require robust API testing capabilities.
  3. Data-Driven Testing Needs: Teams that require data-driven testing will benefit from PyRestTest’s support for parameterization and varied test data.
  4. Basic to Intermediate Testing Requirements: For projects with basic to intermediate testing needs, PyRestTest provides all necessary functionalities without the overhead of more complex tools.
  5. Integration with CI/CD Pipelines: Teams looking to integrate API testing into their continuous integration and deployment workflows will find PyRestTest’s command-line interface and automation capabilities beneficial.


PyRestTest is a valuable tool for API automation and testing, offering a straightforward, lightweight, and extensible solution. Its YAML/JSON-based test definitions, comprehensive assertions, and ease of integration with CI/CD pipelines make it an excellent choice for developers and QA professionals. While it may not have all the advanced features of more comprehensive tools, its simplicity and open-source nature provide significant benefits, particularly for individual developers, small teams, and projects with budget constraints.

PyRestTest is well-suited for basic to intermediate testing requirements, making it a versatile tool in the API testing landscape if you are from python ecosystem.

About the author
Irfan Ahmad

Irfan Ahmad

Software Quality Leader | Helping software teams to deliver with speed, security and scale.

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