Skip to content
Utiloom

OpenAPI Inspector & Validator

Validate bounded OpenAPI YAML or JSON in an isolated worker and inspect endpoint, response, operation ID, path parameter, and security evidence.

LocalNo contract retention

Reviewed July 13, 2026

Guide, examples, and validation Show

About this tool

Review an API contract as both a standards-validated document and an actionable endpoint inventory without resolving remote references.

  • Parses bounded YAML or JSON with alias, merge, depth, node, operation, warning, and execution limits before Swagger Parser validation.
  • Resolves local references for inventory but rejects every external $ref before validation without making a network request.
  • Reports endpoints, responses, operation IDs, path parameter declarations, applied security, deprecation, request bodies, deterministic review warnings, and timestamped JSON evidence.

How to use OpenAPI Inspector

Paste or load an OpenAPI document, parse and validate it locally, then review operations, security declarations, schemas, and unresolved references.

When this tool is useful

  • Reviewing an API contract before documentation or generation.
  • Finding missing operation metadata and broken local references.

Practical tips

  • Do not paste production secrets into example values.
  • Run generated clients and requests separately.

Examples you can test

Load an example, compare the result with the expected output, then replace it with your own input.

Inspect a small API contract

Example input

OpenAPI 3 document with one GET operation and a broken local $ref

Expected output

Operation inventory plus reference validation error

A valid document does not prove the deployed API behaves the same way.

Validation checklist

  • Resolve parser and reference errors.
  • Review security requirements per operation.
  • Compare the contract with the deployed API separately.

Frequently asked questions

Are remote $ref files loaded?

No. External reference resolution is disabled in this public browser workflow.

Which versions are supported?

Swagger/OpenAPI 2.0 and OpenAPI 3.0 and 3.1 documents are supported by the validation engine.

Is the API document uploaded?

No. YAML parsing, validation, inventory, and report export run in your browser.

Related tools

Keep the workflow moving

Continue with tools that handle a related input, output, or validation step.

Developer

CSV & Local Data Workbench

Profile, clean, and convert CSV data locally.

Local
Developer

JSON Schema Workbench

Validate bounded JSON Schema and instance data locally.

Local
Developer

Accessibility QA Workbench

Review WCAG contrast and isolated HTML audit evidence.

Local
Developer

ASCII Table

Search, inspect, copy, and export standard ASCII codes.

Local