Skip to content

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.

Core benefits:

  • 🔍 Discovers edge cases that break your API with unexpected input
  • ⚡ Zero test maintenance - adapts as your schema evolves
  • 🛡️ Prevents regressions by testing API contracts
  • 📊 Validates specification compliance between implementation and documentation

Try the demo

Test a sample API using uv:

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

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'

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 - 15-20 minute hands-on workflow with a realistic booking API

For release testing and security assessments, see Optimizing for Maximum Bug Detection

Reference guides: