How our email verification works

Free Email Verifierchecks whether an email address can actually receive mail. Every check runs in two stages: a safety scan that happens inside your browser, and a server-side verification that talks to the address's mail infrastructure.

Stage 1: the local safety scan

When you paste a list or drop a CSV file, nothing is uploaded. Your browser parses the file, pulls out every address, removes duplicates, and screens each one against three local checks: address syntax, a list of known disposable email domains, and a list of role-based local parts like info@ and support@. Anything caught here is labeled instantly and never counts against your daily quota.

Stage 2: server-side verification

Clean candidates are sent to our verification engine one at a time over HTTPS. For each address we resolve the domain's MX records to confirm it has live mail servers, then perform an SMTP-level conversation with those servers to test whether the specific mailbox is accepted, without ever sending an email to it.

What the verdicts mean

• Deliverable. The mail server confirmed the mailbox exists and accepts mail.
• Risky. Mail might arrive, but something lowers confidence: a catch-all domain that accepts every address, a role account, or a disposable provider.
• Invalid. The address is malformed, the domain has no mail servers, or the mailbox was rejected. Sending here will bounce.
• Unknown. The mail server would not give a definitive answer in time. Failed checks are not charged to your quota.

Data handling

Lists stay in your browser. Only the individual addresses you choose to verify are sent to our servers, one at a time. Verification results are cached for up to 24 hours so repeated checks are instant, and daily usage counters are kept to enforce the free limits. We do not sell, share, or build marketing lists from checked addresses. See the privacy policy for specifics.

The free limits

You get 10 verifications a day with no signup. Entering your email raises that to 100 a day, free, with no password and no credit card. Limits reset at midnight UTC. Questions? Write to [email protected].