SimpleVerifier Team · Reviewed
Can you check if an email address exists without sending an email?
Yes, in many cases. A verifier looks up the domain's mail servers, connects over SMTP, asks whether the server would accept mail for the address, and disconnects before any message is sent. It works where the provider answers honestly, and cannot confirm addresses at catch-all domains or providers that accept everything.
What the check can and cannot prove
Gmail, Google Workspace, Proton and Zoho said a made-up mailbox did not exist in our 23 October 2026 tests, so a check there is reliable. Yahoo and AOL accepted every address, and Microsoft consumer domains and iCloud do not confirm mailboxes, so those return risky. The free single checker needs no account.
Related questions
- Does checking an address notify its owner?
- No. The connection ends before the message-sending step, so no email is delivered or shown to the recipient.
Sources
- RFC 5321: Simple Mail Transfer Protocol
- How mailbox providers answer verification checks, 2026 (SimpleVerifier study, 51 providers, CC BY 4.0)
Figures marked as ours come from SimpleVerifier’s own dated tests on made-up addresses, published with their data on the research page. No customer data is used, and we publish no accuracy percentage because we have no independent measurement to back one.
Do it now
Test it on a real address first
Type any address. It gets the same check the paid plans run: syntax, the domain’s mail servers and, where the provider allows it, a live mailbox check. Nothing is sent to the address.
Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.
Have a list? Sign in with Google and the first 100 addresses are checked free, with results to download. No card.
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