Every JSON error includes error.code, error.message, and error.requestId. Pending discovery returns 202 with Retry-After. Throughput and monthly-limit failures use distinct 429 codes.
Quota headers report the limit, remaining successful requests, and reset time. Pending, missing, fallback, error, HEAD, and 304 responses do not consume the monthly allowance.
{
"error": {
"code": "discovery_pending",
"message": "We are checking this domain.",
"requestId": "req_01J…",
"retryAfter": 10
}
}