Free Email Address Validator

What this email validator checks

Most bad addresses on a list are not malicious, they are mistakes: a fat-fingered domain, a role mailbox someone typed instead of their own, or a throwaway address created to get past a signup form. Each one costs you the same as a real address when you send, and a high enough share of them will push your bounce rate into the range where mailbox providers start throttling or blocking your mail outright. Catching them before they enter your list is far cheaper than repairing a damaged sending reputation afterwards.

This tool runs the following checks against the address you enter:

• Syntax — whether the address is shaped correctly, with a single @, a valid local part, and a domain with a plausible top-level domain.
• Typo detection — near-misses of the major mailbox providers such as gmial.com or hotmial.com are flagged with the correction, because these are recoverable if you catch them at signup.
• Disposable domains — the domain is compared against a continuously updated database of temporary and throwaway mail providers. High-risk domains are separated from merely disposable ones.
• Role accounts — shared mailboxes such as info@, support@ and sales@ are identified. They are valid but rarely belong to one person, and they attract complaints.
• Spam-trap patterns — local parts that look seeded rather than human, like repeated characters or long digit strings. Mailing a trap is one of the fastest ways to get blacklisted.
• MX records — whether the domain actually publishes mail servers. A domain with no MX record cannot receive mail at all, so every send to it hard-bounces.
• SPF and DMARC — whether the domain publishes sender authentication. This says less about the individual address and more about how seriously the domain is administered.

Why bounce rate matters more than list size

Mailbox providers judge senders on engagement and hygiene, not volume. A list of 10,000 addresses with a two percent bounce rate will reliably outperform a list of 50,000 with a fifteen percent bounce rate, because the second list signals that you do not verify who you are mailing. Once that signal is established, even your mail to valid recipients starts landing in spam. Validation is the cheapest lever you have on inbox placement, and it works before you have spent anything on sending.

Hard bounces are the most damaging because they are unambiguous: the domain or mailbox does not exist. Those are exactly the addresses this tool identifies through the syntax and MX checks. Soft signals such as role accounts and disposable domains do not bounce, but they depress open rates and raise complaints, which feed the same reputation calculation.

Fixing what the check finds

If the domain has no MX record, remove the address — there is no configuration that makes it deliverable. If a typo is suggested, the address is usually salvageable: confirm the correction with the subscriber rather than silently rewriting it, because guessing wrong creates a complaint from someone who never signed up. Disposable addresses are best blocked at the point of signup rather than filtered later, which is why the same disposable-domain database is available to the desktop app during list import.

If the check flags a missing SPF or DMARC record on a domain you control, the SPF, DKIM and DMARC checker will show you exactly what is published today, and the DNS record generator will produce the records you need to add.

Single checks here, bulk validation in the app

This page is deliberately limited to one address at a time. Live SMTP verification — actually opening a conversation with the receiving mail server to confirm a specific mailbox, detect catch-all domains and handle greylisting — is part of the email validation feature in PMTAcore, along with CSV import, parallel processing, quality scoring across an entire list, scan history and CSV export. You can try it on the free trial.