Email check

Check email addresses for syntax, domain, MX and typos

Paste addresses one per line or any text that contains them. The check finds syntax errors, domains without mail, disposable mailboxes and typos in popular domains.

Addresses

Only the domain mail server knows whether a mailbox exists, and it only answers over SMTP on port 25. Browsers cannot open that port, so the check covers everything visible from outside: syntax, domain DNS and lists.

What the check covers

First the syntax: length, allowed characters, dots in the mailbox name and the domain after @. Internationalized domains get converted to Punycode, the way a mail server does it.

Then the domain DNS. Without MX and without an A record mail has nowhere to go, and the MX record 0 . means the domain accepts no mail at all. The check sends one DNS query per domain, so a thousand gmail.com addresses take a second.

Disposable domains come from the open disposable-email-domains list with over 9,000 services like mailinator.com. Typos get matched against popular mail domains: gmial.com, hotmail.con, yahho.com.

When it helps

You clean a list before a campaign to avoid bounces and spam complaints.
You check sign-up form addresses and block disposable mailboxes.
You catch typos in customer addresses before an order email goes nowhere.
You remove shared mailboxes like info@ and sales@ from a list for personal emails.

Questions and answers

01Can I check whether a mailbox exists?

Only the domain mail server knows for sure. Services that promise this connect to it over SMTP and start sending a message. Many servers say yes to any address or block the checker. This check finds addresses mail cannot reach and addresses with risk.

02What is wrong with disposable addresses?

Such a mailbox lives from ten minutes to a couple of days. People enter it to grab a bonus or a file, later mail goes into the void, and bounces hurt the sender reputation.

03What is a role address?

A shared team mailbox: info@, sales@, support@. Several people read it, and one of them will click Report spam. Remove such addresses from marketing lists.

04Do my addresses go anywhere?

No. Your browser processes the list. Only DNS queries with domain names go out to Cloudflare or Google, mailbox names stay with you.

05Which typos does the check catch?

Mistakes in the domains of popular mail services, such as gmial.com for gmail.com, and in the zone: .con for .com, .ry for .ru. The check suggests the right domain, and you decide whether to fix the address.