OpenAPI / Swagger Validator — Free Online Tool
Validate OpenAPI 3.x and Swagger 2.0 spec files in JSON or YAML format. Checks required fields (openapi, info, paths), operation completeness, and path naming conventions. Shows errors, warnings, and a summary of paths and operations.
100% client-side. No uploads. Your data never leaves your browser.
How to use OpenAPI / Swagger Validator
- Paste your OpenAPI JSON or YAML.
- Click Validate.
- Review errors (required fields) and warnings (best practices).
- Fix issues and re-validate.
Frequently Asked Questions
What OpenAPI versions are supported?
OpenAPI 3.x and Swagger 2.0 are detected and validated. The tool checks required structure but does not validate JSON Schema constraints within schemas.
Can I validate YAML?
Yes. Paste OpenAPI YAML directly — the tool auto-detects JSON vs YAML.
Does this replace a full OpenAPI linter?
No. This is a structural validator that checks required fields and basic conventions. For production use, use tools like openapi-generator or Spectral for full validation.
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