How the free email verifier works
Every check runs four tests in under a second. First we check the syntax, because an address with a typo or a missing piece can never be valid. Then we look up the domain's mail servers (the MX records) to confirm it can receive mail at all. Next we open a connection to that mail server and ask whether the specific mailbox exists, without ever delivering a message. Finally, for domains that accept everything, we run a catch-all probe to tell a real signal from a blanket "yes".
What each result means
- Valid: the mailbox exists and accepts mail. Safe to send.
- Invalid: the mailbox does not exist or cannot receive mail. Remove it before you send.
- Catch-all: the domain accepts any address, so the exact mailbox cannot be confirmed. Send with caution.
- Disposable: a throwaway address from a temporary-inbox service. Almost never worth keeping.
- Unknown: the mail server would not give a clear answer this time. We tell you honestly rather than guess.
Why verify before you send
Every email that bounces is a small mark against your sender reputation. Send to enough dead addresses and Gmail, Outlook, and Yahoo start routing your mail to spam, even for the people who do want to hear from you. Verifying first keeps your bounce rate low and your inbox placement high. If you want the full picture, read our complete guide to email verification or see how we stack up in the best email verification services comparison.
Frequently asked questions
Is the email verifier really free?
Yes. You can run real checks right here with no account. When you sign up you get 100 free verifications with no credit card, which is enough to clean a small list or test the engine on your own data.
Do you send an email to verify the address?
No. The check is silent. We talk to the receiving mail server the same way a sending server would, up to the point of asking whether the mailbox exists, then stop before any message is delivered. The person being checked never gets an email.
How accurate is it?
We verify at around 99.6% accuracy. Accuracy is highest on Gmail, Outlook, and Yahoo, and the hard cases are catch-all domains, which we actively probe instead of guessing. No verifier is perfect on every address, so we are honest when a mailbox genuinely cannot be confirmed.
What does 'catch-all' mean?
A catch-all domain accepts mail to any address, even ones that do not exist, so a single check cannot prove one specific mailbox is real. We probe a real and a fake address in the same session to get a usable signal rather than just labelling it risky.
Can I verify a whole list at once?
Yes. Upload a CSV or Excel file and we verify the entire list, remove duplicates, and give you a clean file back. Create a free account to run a bulk job.
Clean your whole list, free to start
Create an account for 100 free verifications. No credit card. Upload a CSV and get a clean list back in minutes.
No credit card · 99.6% accuracy · real-time