Email validation for signup forms, lead lists and CRM cleanup: checks syntax, MX mail servers, disposable or temporary domains, role addresses (info@, sales@) and free providers. Returns a deliverable_guess. No SMTP probe, no data stored. Price $0.001 USDC per call via x402. Example output: {"email":"jane@acme.com","valid_syntax":true,"domain":"acme.com","mx_records":["10 mx1.acme.com."],"has_mail_server":true,"disposable":false,"role_account":false,"free_provider":false,"deliverable_guess":"likely"}