Adult AI platforms need age verification that satisfies Mastercard MMP Section 9.4.1 and Visa's Integrity Risk Program (VIRP). The five vendors merchants pick from in 2026 are AgeID, Veratad, Ondato, Yoti, and Persona. Coverage geography, verification methods (document, credit-header, digital identity, question-based), VIRP compliance status, price signal, and integration effort vary meaningfully. Clay Pay routes adult AI files to acquirers and packages the age-verification proof at boarding.