OpenAPI and Swagger Validator

Validate a document before sharing it

Paste JSON or YAML and run validation. Structural checks use the published Swagger 2.0 and OpenAPI schemas. The endpoint list shows methods, paths, operation IDs, parameters and response codes. Switch between full documentation and the endpoint list, then download the report or export the specification as JSON/YAML. Format conversion does not upgrade the specification version.

paths:
  /users/{id}:
    get:
      operationId: getUser
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: integer
      responses:
        '200':
          description: A user

References stay inside the document

A reference such as #/components/schemas/User is resolved as a JSON Pointer. Missing targets are errors. References to other files or HTTPS URLs are left unresolved and explicitly reported, rather than silently fetched. A document with unresolved external references has an incomplete reference check even when its structure passes.

Swagger 2.0 and OpenAPI 3.x

Swagger 2.0 uses host, basePath and schemes for server locations, definitions for reusable schemas, and body/formData parameters. OpenAPI 3.x uses servers, components and requestBody. These documents are checked in their original dialect; export changes serialization, not the API version.

OpenAPI 3.0 and 3.1 are different

OpenAPI 3.0 uses its own Schema Object subset, including nullable. OpenAPI 3.1 aligns with JSON Schema 2020-12 and supports a schema dialect. This tool checks the surrounding 3.1 document structure but does not fully validate embedded Schema Objects or custom dialects. Use the JSON Schema Validator to test a schema against data.

To inspect actual traffic, use the HAR analyzer. To turn a captured request into code, use the cURL converter.

An OpenAPI description documents HTTP APIs. For a GraphQL query or schema document, use GraphQL Formatter to inspect supported syntax instead; that tool does not validate a request against your running service’s schema.

Frequently asked questions