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OpenAPI Specification Inspector

Review supported OpenAPI document structures and list operations, parameters and response codes.

Inputs stay on your device No sign-up Free to use
How this works

The tool runs in this browser. Your file or text is not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Privacy details

Showing an example. Edit to see your own.

100,000 UTF-8 bytes, 100 paths and 200 operations. YAML anchors, aliases, tags, merges and repeated keys are refused.

Processed in your browser. Your inputs stay on this device.

How to use OpenAPI Specification Inspector

  1. Paste a supported JSON or YAML specification.
  2. Run the structural review.
  3. Inspect issues and the operation inventory before changing or publishing the specification.

Example: OpenAPI Specification Inspector

An OpenAPI 3.0 document with one GET /pets operation and a 200 response.

You add
OpenAPI or Swagger JSON / YAML: openapi: 3.0.4 info: title: Example API version: 1.0.0 paths: /books/{id}: get: operationId: getBook parameters: - name: id in: path required: true schema: type: string responses: "200": description: A book
You get
Inspected OpenAPI 3.0.4: 1 operations, 0 structural findings. Sample rows: GET | /books/{id} | getBook | path:id | 200.

Options

Specification version
Choose a document whose declared version is supported. Swagger 2.0 and supported OpenAPI 3 versions have different parameter and response structures.
Operation inventory
Review the listed method, path, parameters and response codes. These are declarations from the supplied document, not observations of a running API.

Supported inputs and limits

Structural review for named supported specification versions only, not complete conformance or a security audit. JSON or safe YAML; unsupported versions and references require review. No external reference resolution, API calls, authentication or URL fetch. YAML aliases, merges, custom tags and duplicate keys are refused. Supported versions: Swagger 2.0; OpenAPI 3.0.3, 3.0.4, 3.1.0 and 3.1.1. A review result always leaves complete conformance unverified.

Where your input is processed

This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Resolve the gaps in the intended toolchain

External references are not fetched and full specification conformance remains unverified. Use the inventory to find the relevant operation, then check unresolved references and complete validation in the API’s toolchain. A declared response or security requirement does not establish what the actual server returns or enforces.

Questions about OpenAPI Specification Inspector

Will this contact my API?

No. Paths and server URLs are read as document values only.

Does it validate every OpenAPI schema rule?

No. The result lists the supported structural checks and remaining review limits.

What happens to external references?

They are not fetched or resolved; the result identifies what still needs review.

Project manager: Tony Hines · Content updated 4 October 2026 · Report a problem

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