6 email validation checks in one call — syntax (RFC 5322), MX record verification, disposable detection (5,000+ domains), free provider identification, role-based address detection (admin@, info@), and typo suggestion. Returns a 0-1 confidence score with detailed per-check results. POST method protects email addresses from access logs. No API keys, no multiple service integrations needed. Accepts USDC payments on Base and Solana