API & OpenAPI utility
OpenAPI Validator
Check OpenAPI documents for valid YAML or JSON and essential structure.
● This tool runs entirely in your browser. Your input is never uploaded to our servers.
Output
Your result will appear here…
How to use OpenAPI Validator
- Paste an OpenAPI 3.x document in YAML or JSON.
- Select Validate to check syntax and core structure.
- Review any issue; this lightweight check is not a full schema validator.
Example
Input:
{"openapi":"3.0.3","info":{"title":"Example API","version":"1.0.0"},"paths":{"/health":{"get":{"responses":{"200":{"description":"OK"}}}}}}Output:
Valid OpenAPI structure ✓ Version: 3.0.3 Paths: 1 Operations: 1
Use cases
- Catch missing required top-level fields.
- Check an API document before reviewing it.
- Validate a local draft without uploading it.
About this tool
Check OpenAPI documents for valid YAML or JSON and essential structure. Processing happens locally in your browser, so your input is not sent to a server or included in analytics.
Frequently asked questions
Does this validate every OpenAPI schema rule?
No. It checks syntax and essential structure, not the complete OpenAPI schema or all reference targets.
Are remote references fetched?
No. The validator does not make network requests or resolve remote references.
Which formats are supported?
OpenAPI 3.x documents written as JSON or YAML are supported.