FREE DEVELOPER UTILITY · OPENAPI 3.0 / 3.1

A first look at your API
before it breaks.

Spot missing response contracts, unresolved local references, path parameter errors and duplicated operation IDs. Paste an OpenAPI JSON spec or load a file; see actionable findings in seconds.

Need an example? Read the independently verified OpenAPI 3.0 YAML sample and public HTTP evidence ↗ (26 tests, 0 lint errors, 2 disclosed warnings).

↳ Browser-only processing↳ No account required↳ No spec uploads
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Your API specification stays on this device.

Analysis uses a local JavaScript module with no network requests, tracking, remote fonts or storage. You control the input and can clear it whenever you want.

01 / INPUT

OpenAPI JSON

JSON · MAX 750K CHARACTERS

Paste a public or authorized OpenAPI 3.x JSON specification. Don't paste API keys, authentication tokens, user data or secret examples.

For YAML, export a JSON version first. External URLs and $ref destinations are never fetched.0 characters
No server · No upload · No sign-in
02 / RESULT

Findings

NOT YET ANALYZED

Make the contract observable.

Your errors, warnings and documentation notes will appear here with the affected JSON pointer and a suggested next step.

NEED A MORE THOROUGH CHECK?

From a hint to a test you can rerun.

VM5 Delivery Lab offers fixed-scope API quality checks with reproducible scripts and clear acceptance criteria. Share only a sanitized problem statement in the external Google Forms inquiry; no secret specs or customer data.

Ask for an API review ↗Inspect the utility source ↗