Email verification
Email verification is the process of checking whether an email address is valid and safe to send to — confirming the syntax, domain and mailbox exist and aren't a known trap or disposable address — before you add it to a campaign. It is the single most effective way to control bounce rate.
How it works
A verifier checks format, validates the domain's MX records, and probes the mailbox (without sending) to classify the address as valid, invalid, catch-all or risky.
Why it matters
Sending to unverified lists spikes bounces and spam-trap hits, which damages sender reputation across all your mail. Verifying first is far cheaper than recovering a burned domain.
How Autocloz handles it
Autocloz includes email verification (1,000/day on the free plan, more on paid) and verifies addresses before sending, auto-suppressing invalid ones so a bad import can't tank your reputation.
FAQ
How accurate is email verification?
For most mailboxes it reliably flags invalid and disposable addresses. Catch-all domains accept any address, so verifiers mark them 'risky' rather than valid — send to those cautiously.
Related terms
Email bounce rate is the percentage of sent emails that are returned undelivered. Hard bounces are permanent (invalid or non-existent address); soft bounces are temporary (full mailbox, server down). A high bounce rate signals a poor list and damages sender reputation.
A spam trap is an email address operated by mailbox providers and blocklist operators specifically to catch senders with poor list hygiene. There's no real person behind it, so any mail it receives indicates you're emailing addresses you didn't earn permission to contact.
A hard bounce is a permanent email delivery failure — the address is invalid, the domain doesn't exist, or the mailbox was deleted — and should be suppressed immediately. A soft bounce is a temporary failure — a full mailbox, a message too large, or a server briefly down — which may succeed on a later retry.
List hygiene is the ongoing practice of keeping an email list clean and accurate — verifying addresses, removing invalid and hard-bounced contacts, suppressing unsubscribes and long-term non-engagers, and avoiding purchased or scraped data. Good hygiene protects deliverability and keeps sender reputation healthy.