Free tool · no signup
Email verifier
Paste any business email address. We check the format. We ask DNS if the domain runs a real mail server. Those two checks catch most dead addresses, before you waste a send.
Enter an address. We check its format, then ask DNS if the domain can receive mail.
Only the receiving server can prove a mailbox exists. Leadistry leads go further. Every email we deliver is checked against the company's own website and Companies House records. Try 25 free leads, no card needed.
Three layers, two run right here
Is it shaped like a real address? One @, a valid domain, no illegal characters.
Does the domain publish mail servers? Without them it cannot receive email at all.
Only the receiving server proves a mailbox exists. We check against the company's own site.
Is the email domain valid?
That is the question the second layer answers, and it is usually the one worth asking first. An address can be spelled perfectly and still be undeliverable because the domain behind it publishes no mail server. Checking the domain is also the cheapest check there is: one lookup rules out every address at that company, not just the one you pasted.
What this check actually does
Every email address carries two public facts. Is it valid in shape? And can the part after the @ receive mail at all? The first is a format check. Every mailbox provider enforces the same rules: one @, a real domain shape, no illegal characters. The second is a DNS lookup for MX records. Those are the servers that accept mail for that domain. A domain with no MX records cannot receive email. Any address on it is dead, however real it looks.
Those two checks catch most of the bad addresses on a prospect list. Typos. Dead domains. Companies that changed their name. Addresses someone guessed from a name pattern. What they cannot do is prove a mailbox exists on a working domain. That needs an SMTP conversation with the receiving server. Even then, roughly a third of business domains are catch-all. They accept every address and tell you nothing.
Why bounce rate matters more than list size
Mailbox providers score senders. Every bounce drags your domain's reputation down. Hard bounces to addresses that never existed hurt the most. Then the mail you send to real people starts landing in spam. Keeping bounces under 2 to 3 percent beats any subject-line trick. That is why checking a list before you send is the best habit you can build. Sending cold email? Pair this with the sending-domain checker, so your own SPF, DKIM and DMARC records are in order too.
Frequently asked questions
Also free: the sending-domain checker (SPF, DKIM, DMARC). Or skip list-cleaning entirely: Leadistry delivers UK leads with pre-verified emails from Companies House data.
How do I check if an email domain is valid?
Paste the address above. The second layer of the check asks DNS whether the domain publishes MX records, which is what tells you the domain can receive mail at all. A domain with no MX records is not a valid email domain: nothing sent to it will arrive, no matter how the address is spelled. That check is free here, needs no signup, and is the fastest way to throw out a whole batch of dead addresses at once, because a broken domain kills every address on it rather than one.
How does an email verifier work?
In three layers. First, syntax. Is the address even shaped like an email? Second, DNS. Does the domain publish MX records? That means it runs a real mail server. Third, SMTP. You connect to that server and ask if the mailbox exists. This free tool runs the first two layers. They catch most dead addresses. Only the receiving server can prove the third.
What is a catch-all domain?
It is a domain set up to accept mail for any address, even ones that do not exist. Catch-all domains say yes to every mailbox check. So no verifier can prove a mailbox is real on them. Roughly a third of business domains work this way. The honest answer for those is 'risky', not 'valid'.
Why do verified emails still bounce sometimes?
Mailboxes get deleted between the check and the send. Servers greylist senders they do not know. Catch-all domains accept everything, then bounce it later. Checking first cuts bounces a lot. No tool can get them to zero. Keep your bounce rate under 2 to 3 percent and your sender reputation holds up.
Is it safe to check an email address here?
Yes. The check reads public DNS records for the domain. We do not send anything to the address, we do not store the addresses you check, and no signup is needed.
How is a Leadistry lead's email different?
Leadistry never guesses first.last@domain patterns. Every email we deliver was published by the company itself, usually on its own website. We then check it against Companies House records and the domain's mail setup. If we cannot verify an email, it is not a lead. You are not charged for it.
Skip the list-cleaning. Get leads that arrive verified.
25 free leads. Every email is cross-checked against the company's own site and Companies House. No card.
Start free with 25 leads →✓ No card · ✓ 25 free leads · ✓ Cancel anytime