Email Validator

Email Validator checks that an address is correctly formatted, then looks up its domain's MX records to confirm that domain is actually configured to receive mail at all.

Use this to catch an obviously mistyped address before it bounces, when cleaning up a mailing list and wanting to filter out addresses on domains that plainly cannot receive mail, or when troubleshooting why a message to a specific address never arrived.

This cannot confirm that the specific mailbox exists, only that the address is well formed and its domain accepts mail in general. Actually verifying a mailbox would mean attempting real delivery, which mail providers treat as exactly the kind of probing behaviour that gets a sending server blacklisted.