HTTP 401
invalid_api_keyInvalid API key
The supplied API key is invalid, expired, or revoked.
Resolution
Create or rotate a key in the developer portal.
Response handling
Keep the response's request_id for diagnostics. Retry only transient rate limits and 503 responses, respecting Retry-After with bounded exponential backoff and jitter. For monthly_quota_exceeded, stop polling until RateLimit-Reset or upgrade. Correct 400, 401, 403, and 406 requests before retrying.