Email verification

Email verification runs a set of checks on an address. It tests the syntax, whether the domain exists and has an MX record, and whether the mail server says the mailbox exists. It can also flag disposable addresses, role-based addresses such as info@ and catch-all domains.

It cannot be perfect. Some servers accept every address and bounce later, some hide the answer on purpose, and addresses change over time. A result is a good guess, not a promise. A verified list from last year can still contain many dead addresses.

Verify a list shortly before you send, not months before. Remove addresses that fail, treat 'risky' ones with care and send to them in small batches. Verification does not replace good list sources. It also does not make a mismatched audience reply. Used with a small first batch, it is the best way to keep the bounce rate low.