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Online Email Checker

Email

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Whether an address exists: syntax, MX record and the mail server’s answer.

Why check an address

Sent an email and heard nothing back? Check whether the address and mailbox exist, and confirm the contact details are still current.

Before a campaign Every message to a dead address damages your sender reputation. Above two per cent of them, mail providers start routing the whole campaign to spam.
Typos in forms gmial.com instead of gmail.com is the classic. The domain exists, the message sends, no reply ever comes. We flag these separately.
Disposable inboxes Addresses that live for ten minutes. Someone claimed a discount and vanished; writing there is pointless.
Role addresses info@, admin@ and support@ are read by a department, not a person. They rarely reply and report spam more often.
Verifying a client contact The address was dictated over the phone or written by hand. A minute of checking instead of a week of waiting.

How the check works

In short: we send a greeting to the mail server for that address and get an answer. Or we do not, and the address is marked as non-existent.

1 Syntax Whether it looks like an address at all: one @, a domain with a dot, length within the standard. Obvious typing errors stop here.
2 The domain MX record We look for a mail server on the domain. No MX record means the domain accepts no mail at all, and there is nothing further to check.
3 A conversation with the server We say hello and ask whether it would accept mail for that address. A 250 means yes, a 550 means no such mailbox. No message is actually sent.
4 The catch-all test We also ask about a deliberately invented address on the same domain. If the server accepts that too, its yes means nothing, and we mark the result unknown.

Why the result is not always final

Accuracy depends on how the mail server is configured. The most reliable results come from the major providers: Google, Yahoo, Outlook and similar.

The server stays silent on purpose A “does not exist” verdict does not mean the address is truly absent. The mail server may simply be configured not to answer such greetings, precisely to make these checks impossible.
The server accepts everything Catch-all mode: the domain accepts any address and sorts it out later. Then “exists” proves nothing either, and we say so.
A temporary refusal A 4xx code means “try later”: greylisting, rate limits, temporary load. An hour on, the answer may differ.
The most reliable method Try sending an actual message. If no error report arrives within a day, the address most likely exists. The error may also appear in your own mail server logs if you run one.

What each result means

Exists The server confirmed it would accept mail while rejecting the invented address. The strongest result available.
Does not exist The server refused outright with a 5xx, or the domain has no mail server. Remove these from your list.
Unknown The server gave no clear answer: catch-all, a temporary refusal or silence. Not “bad” but “could not be verified”.
Syntax error The address does not match the format: no @, no dot in the domain, or too long. It never reaches a server.

What to do with the result

Remove the dead ones The fastest way to improve deliverability. Two per cent of bad addresses already harms your domain reputation.
Fix the typos We suggest the right domain where we recognise it. Often a message through another channel settles it.
Set up your own mail A clean list will not help if your domain lacks SPF, DKIM and DMARC. Check your <a href="/en/tools/spf/">SPF record</a>, <a href="/en/tools/dkim/">DKIM signature</a> and <a href="/en/tools/dmarc/">DMARC policy</a>.
Check the blacklists On shared hosting hundreds of sites share an IP, and one spammer among them breaks delivery for everyone. An <a href="/en/tools/rbl/">IP check</a> takes a minute.

If campaigns matter to your business and mail still does not arrive, we set up domain email end to end: your own server, authentication records and backups. <a href="/en/contact/">Get in touch</a>.

FAQ

Is the email checker free?
Yes, with no registration. Up to 50 addresses at a time, pasted as a list or uploaded as a file. The file is read in your browser and never reaches our server.
Do you send a message to the address?
No. We only greet the mail server and ask whether it would accept a message. The conversation stops before any mail is transferred, so the owner receives and sees nothing.
Why does it say “unknown” instead of yes or no?
Because the server gave no clear answer. Usually it accepts any address on the domain, refused temporarily with a 4xx, or does not respond to such requests at all. We think “could not verify” is more honest than a guess.
How accurate is the result?
For the big providers — Google, Outlook and similar — quite accurate. For corporate domains it depends: many servers deliberately answer identically to everything so that such checks fail.
What is catch-all and why does it interfere?
It is a mode where the domain accepts mail for any address, even invented ones. We test this separately by asking about a deliberately fake mailbox on the same domain. If the server accepts that too, its answer about yours proves nothing.
How can I be certain?
Send a normal message. If no delivery error arrives within a day, the address is almost certainly live. With your own mail server the error would also show in its logs.
Why flag role addresses?
info@, admin@ and support@ technically exist but suit campaigns poorly: a department reads them, replies are rare, and spam complaints arrive more often than average. Not an error, just something to weigh.
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