Real SMTP verification, no guesswork
Bouncebuster checks each address the way a mail server would - but without ever delivering a message. Here’s the full pipeline.
Syntax & normalization
We normalize the address and reject malformed syntax up front, following the same rules mail servers use.
MX lookup
We resolve the domain’s mail exchangers. No mail servers means mail can’t be delivered - the address is invalid.
Live SMTP probe
From dedicated, reputation-managed IPs we open an SMTP conversation and ask whether the mailbox exists - without ever sending an email.
Catch-all detection
We probe a random address on the domain. If the server accepts anything, we mark the domain catch-all so you aren’t misled.
Disposable & role checks
We flag throwaway/disposable providers and role-based mailboxes (info@, support@) so you can decide what to keep.
What you get back
Confirmed at the mailbox level: the address exists and accepts mail. Safe to send.
Bad syntax, no mail server, or the mailbox does not exist. Remove these to stop hard bounces.
The domain accepts mail for any address, so no provider can confirm the exact mailbox from outside. We flag these separately and give you a "valid + catch-all" export, so you decide whether to send.
Temporary or throwaway inboxes from known disposable providers. Usually worth removing.
The mail server wouldn't give a clear answer, usually greylisting or a timeout. Never charged to your account.