Use it before you send to an address, or to screen sign-ups and leads for typos, disposable domains and role addresses. Checks syntax, MX records (with the A-record fallback), null MX, a list of about 120,000 disposable domains, role addresses (info@, support@…) and free providers, without sending anything. No SMTP probing, so it can't confirm the mailbox exists. Never charged for errors: we settl