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Quick Start Guide

Estimated time: 5 minutes

Schemathesis automatically finds bugs in your APIs by generating thousands of test cases from your OpenAPI or GraphQL schema. It catches edge cases that manual testing typically misses.

During the quick-start run Schemathesis:

  • Generates property-based inputs for each operation defined in your schema
  • Runs core checks such as status-code conformance, response validation, and server error detection
  • Reports reproduction-ready commands for any failing cases

Try the demo

Test a sample API using uv:

uvx schemathesis run https://example.schemathesis.io/openapi.json

uvx is from the uv package manager and runs Schemathesis in an isolated environment without a permanent install. Replace uvx schemathesis with schemathesis or st if you have it installed directly.

Example output:

_____________________ POST /improper-input-type-handling _____________________

- Server error

[500] Internal Server Error:

    `{"success":false,"error":"invalid literal for int() with base 10: '\\n'"}`

Reproduce with:

    curl -X POST -H 'Content-Type: application/json' \
      -d '{"number": "\n\udbcd." }' \
      https://example.schemathesis.io/improper-input-type-handling

Test your own API

uvx schemathesis run https://your-api.com/openapi.json \
  --header 'Authorization: Bearer your-token'

For token refresh, per-operation auth, or dynamic credentials, see Authentication.

uvx schemathesis run ./openapi.yaml --url http://localhost:8000

import schemathesis

schema = schemathesis.openapi.from_url("https://your-api.com/openapi.json")

@schema.parametrize()
def test_api(case):
    # Automatically calls your API and validates the response
    case.call_and_validate()

What's next?

Ready to dive deeper?

Complete Tutorial – a 15–20 minute workflow against a realistic booking API

Runs scale with schema size and server performance. For thorough release testing, see Optimizing for Maximum Bug Detection to run longer, higher-coverage sessions.

Reference guides: