OpenAPI Validator vs OpenAPI Viewer
The validator focuses on correctness and actionable diagnostics. The OpenAPI / Swagger Viewer focuses on browsing endpoints, schemas, parameters, and responses in a readable inspection view.
OpenAPI Validator
Paste an OpenAPI or Swagger spec and validate its structure, required fields, paths, operations, schemas, and common mistakes.
Spec input
JSON or YAML OpenAPI 3.x and Swagger 2.0 specs. Remote references are reported, never fetched.
Validation report
Grouped errors, warnings, compatibility notes, summary metrics, and source-free report export.
Ready to validate an API spec
Paste JSON or YAML, load a sample, then validate required fields, paths, operations, responses, schemas, refs, tags, and security schemes.
OpenAPI Validation Guide
Validate OpenAPI and Swagger specs before sharing them
Use this validator to catch structural problems in pasted API descriptions: required top-level fields, paths, operations, parameters, responses, schemas, security schemes, refs, tags, and version-specific fields.
OpenAPI 3 vs Swagger 2
Swagger 2.0 uses swagger, host, basePath, definitions, and body parameters. OpenAPI 3.x uses openapi, servers, components, and requestBody.
Common validation errors
Frequent issues include missing info.title, missing info.version, empty paths, duplicate operationId, missing responses, unresolved local refs, and invalid path methods.
Response and schema quality
Helpful specs include response descriptions, request and response schemas, parameter schema details, declared security schemes, and reusable components or definitions for common objects.
Remote ref limitations
Remote $ref values are reported but never fetched. This keeps validation local and avoids contacting private networks, documentation hosts, schema registries, or API servers.
Safe validation workflow
Validate the pasted spec, filter results by severity or keyword, fix errors first, then review warnings and info notes before copying or downloading the source-free validation report.
OpenAPI Validator FAQ
Does this OpenAPI Validator upload my spec?
No. Parsing and validation run locally in your browser.
Does it call API endpoints or servers?
No. The validator reads only the pasted document. It does not execute examples, callbacks, links, operations, external docs, or server URLs.
Does it support YAML and JSON?
Yes. Paste JSON or YAML. The validator auto-detects the input format where practical.
Does it validate Swagger 2.0?
Yes. It detects Swagger 2.0 and applies key Swagger-specific checks such as definitions, host/basePath, parameters, responses, and securityDefinitions.
Does it support OpenAPI 3.1?
Yes. It detects OpenAPI 3.1.x and validates the pasted structure, operations, schemas, refs, and common documentation issues.
Are remote refs resolved?
No. Remote refs are shown as info notes and are never fetched. Local refs inside the pasted document are checked when practical.