OpenAPI / Swagger Validator
Validate OpenAPI 3.x / Swagger 2.0 documents in JSON or YAML.
OpenAPI / Swagger document (JSON or YAML)
Validation results
- errorOperation 'GET /users/{id}' is missing a 'responses' object.
- errorDuplicate operationId 'listUsers' used 2 times.
- warningOperation 'GET /users' has no summary or description.
- warningOperation 'GET /users/{id}' has no summary or description.
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.
Examples
Missing responses
{"openapi":"3.0.0","info":{"title":"A","version":"1"},"paths":{"/x":{"get":{}}}}Output
Error: Operation 'GET /x' is missing a 'responses' object.Related tools
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Frequently asked questions
Version 1.0.0 · Updated 2026-08-10 · Runs entirely in your browser