Email Checker

An email checker is a tool that validates email addresses to determine if they are valid and deliverable. Our email checker performs multiple checks including format validation, MX records verification, and SMTP connection testing to ensure email addresses actually exist.

To verify if an email address is valid, use our free email checker tool. Simply enter the email address and our system will check the format, verify MX records exist, and test SMTP connectivity to confirm the email address is deliverable.

No — and no email verification service can. Whether a mailbox exists is decided by the receiving mail server, and many major providers (such as Outlook/Microsoft and Yahoo), catch-all domains, greylisting and anti-spam protections deliberately do not reveal it to prevent spam and address harvesting. In those cases we honestly return the status "Unknown" instead of guessing. For most common providers and business domains, however, results are reliable.

"Unknown" means we could not get a definitive yes or no from the mail server. The address may well be valid, but the server did not confirm it — for example because of greylisting, a catch-all configuration, or an anti-spam policy that blocks verification probes. We prefer to tell you the truth ("Unknown") rather than report a Valid or Not Valid result we are not sure about.

Some mail servers accept mail for every address (catch-all), delay unknown senders (greylisting), or block verification attempts based on the sender's IP reputation. When that happens we cannot confirm the specific mailbox, so a real, working address may be marked "Unknown". This is a limitation of how those servers are configured, not an error in the check.

A catch-all domain is configured to accept email sent to any address at that domain, even ones that do not exist. Because the server says "yes" to everything, we cannot tell whether a specific mailbox is real — so such addresses are reported as "Unknown" rather than falsely marked Valid.

Check if an email is valid by using our email validator tool. Our email checker performs comprehensive validation including syntax checking, domain verification, and server connectivity testing to ensure the email address exists and can receive messages.

To check if bulk emails are valid, use our bulk email checker tool. You can upload a file with multiple email addresses or paste them directly. Our bulk email validator will process up to 1000 emails at once and provide detailed results for each address.

Email validation helps improve deliverability rates, reduce bounce rates, protect sender reputation, save costs on email campaigns, ensure compliance with regulations, and achieve better engagement with valid recipients.