See an API contract break before production

This demo runs Cryonel's real browser-side OpenAPI diff engine against a fixed before-and-after example. Nothing is uploaded, no account is created, and the result is available immediately.

GET /v1/users/{id}

Required response:
{
  "id": "string",
  "email": "string"
}

GET /v1/users/{id}?expand=...

Required response:
{
  "id": "string",
  "displayName": "string"
}

What the result means

Removing email from a successful response can break clients that read it. Adding the required expand query parameter can break every existing request that does not send it. An optional parameter deserves review but does not force current callers to change, while a new operation or response property is normally additive.

The demo uses the same focused rules as the free OpenAPI Diff tool. API Guard adds scheduled URL checks, stored baselines, change history, and email alerts. It does not replace integration tests, uptime monitoring, release review, or a complete compatibility policy for every OpenAPI feature.