Direct answer
Answer
An unresolved V2 prediction uses native JSON null for gender, not the string "null". A name may be ambiguous or the available evidence insufficient; check result_status and reason when present. Preserve the unknown outcome instead of forcing a category. A successful unknown prediction is billable at the selected tariff. Request or provider errors are separate failures with billing information in meta.usage.
Further reading
Related guidance
Continue with the primary GenderAPI resources used for this answer.