What Is Email Verification?

Verification runs in layers, cheapest first. Syntax comes first and catches malformed addresses and typos without touching the network. A DNS check follows, confirming the domain resolves and publishes an MX record, which rules out addresses at domains that can never receive mail at all.

The last layer is an SMTP check: the verifier opens a conversation with the receiving mail server and asks whether the specific mailbox is accepted, without delivering a message. That is the layer that separates a live mailbox from an address whose domain merely exists.

Valid means the receiving server accepted the mailbox. Invalid means it refused it, so sending would produce a hard bounce. Risky is the honest middle: the server neither confirmed nor refused, which happens with catch-all domains that accept everything, with role addresses such as info@ or support@, and with disposable domains.

In JaxSuite AI each address also carries a 0 to 100 risk score alongside the status, so a sender who wants a stricter cut than the default can set the threshold rather than accept a single verdict. Risky is a judgement call about how much bounce exposure a campaign can absorb, not a defect in the check.

Immediately before sending, because a verification result is a snapshot of one moment. An address checked three months ago and stored as valid says nothing about today, since the mailbox may have been deactivated the week after the check.

This is why purchased contacts in JaxSuite AI are validated fresh at the point of purchase rather than carrying a historical result forward, and why a list that has been sitting in a spreadsheet needs re-checking before it is loaded into a campaign.