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OpenAPI / Swagger Validator

Validate OpenAPI 3.x / Swagger 2.0 documents in JSON or YAML.

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About the OpenAPI / Swagger Validator

Paste an OpenAPI 3.x or Swagger 2.0 document as JSON or YAML to check required root fields, path operations, missing responses, duplicate operationIds, and unresolved $refs, with a summary of endpoints and severity-tagged issues.

Popular uses

  • openapi
  • swagger
  • api spec
  • validator
  • yaml
  • rest api

Examples

Missing responses

JSON{"openapi":"3.0.0","info":{"title":"A","version":"1"},"paths":{"/x":{"get":{}}}}

Output

YAMLError: Operation 'GET /x' is missing a 'responses' object.

Keyboard shortcuts

  • Copy the main outputCtrl / ⌘ + Shift + C
  • Download the resultCtrl / ⌘ + S
  • Share this toolCtrl / ⌘ + Shift + S
  • Reset the inputsAlt + R
  • Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

Read more

Version 1.0.0 · Updated 2026-08-10 · Runs entirely in your browser