2 services carry this tag in their source record. Tags come from the provider, not from us — a tag is a claim about what the service does, not proof that it does it well.
Does the local part (before the @) look all digits? Pure pattern check on the address, no network, with the matched fragment. Building block for signup-risk scoring and list hygiene. $0.01 per check.
Bulk email local part all digits: up to 20 emails in one call, processed concurrently, results in input order with a per-item error field and a failure count. Same answer per item as the single endpoint. Batch enrichment...