Validate an email address before sending: syntax, MX, disposable and role account. $0.005 USDC on Base per call. Returns a verdict of ok, risky or undeliverable with syntax, MX, disposable (CC0 list), role account and free provider flags. Bad syntax returns 400, not charged. Don't use this for confirming a mailbox exists; no SMTP probe is made.
https://api.inboxguardstest.com/v1/email-check