Check any B2B email address in real time. SMTP verification, catch-all detection, MX lookup, disposable filter — all in one tool. 10 free checks per day.
Quick answer
A real email verifier runs four checks in sequence: (1) syntax check (is it a valid email format?), (2) MX record lookup (does the domain have mail servers?), (3) real-time SMTP handshake — connects to the mail server and asks "does this address exist?" via the RCPT TO command, and (4) catch-all detection — tests a random address at the same domain to catch domains that silently accept all mail. This tool does all four, plus flags disposable and role-based addresses. Free, no signup, 10 checks per day.
How it works
RFC-compliant email format check. Rejects malformed addresses.
Checks if the domain has mail servers. Domains without MX cannot receive mail.
RCPT TO handshake with the target mail server. 250 = valid, 550 = invalid.
Tests a random address at the same domain. If accepted, domain is flagged risky.
Upgrade to Scrupp
This free tool verifies one email at a time, 10 checks/day. Scrupp adds:
Upload a CSV of 1,000+ emails, verify all in minutes.
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FAQ
Yes. 10 verifications per day per IP, no signup required. For unlimited verification or bulk CSV upload, create a free Scrupp account.
90-95% accurate on standard corporate domains. Some mail servers (banks, government, Microsoft 365 defaults) block SMTP verification at the server level, which returns "unknown" — in that case, proceed with caution.
A catch-all domain accepts all mail sent to any address (e.g. john@company.com, fake123@company.com, both accepted). The server returns 250 for any email, even non-existent ones. These emails look valid but may silently disappear. Send to them at half rate and monitor reply behavior.
Invalid: the mail server explicitly rejected the address (550/553 response) — don't send. Risky: the address technically accepted but the domain is a catch-all or role-based — send with caution, monitor engagement.
No. Emails are checked in real time and not logged. Only a daily check counter is stored per IP (hashed) to enforce the free limit.
Not on the free tool — this page verifies one email at a time. For bulk CSV upload (1,000+ emails in minutes), create a free Scrupp account at app.scrupp.com.