Free bulk email checker
Paste up to 10 emails (one per line or comma-separated). Instant DNS + disposable check for each. No signup.
When you'd use bulk checking
- → Clean a small list. Before importing 25 leads into your CRM.
- → Test a competitor's list. Quickly sample-check if it's hygenic.
- → Verify CSV before upload. Catch obviously broken addresses before paying to verify the whole list.
Free vs paid bulk verifier
| Feature | Free tool | MailoClean |
|---|---|---|
| Emails per check | 10 / batch | 50,000+ |
| Syntax + MX + Disposable | ✓ | ✓ |
| Live SMTP mailbox check | - | ✓ |
| Catch-all detection | - | ✓ |
| CSV download (valid / invalid / risky) | - | ✓ |
| Accuracy | ~80% | 99% |
| Price | Free | From $0.008/email |
How the free bulk checker actually works
Every email in your list goes through the same four-step pipeline as our single-email tool - just batched so you see all the verdicts together:
- 1. Syntax (RFC 5321 compliant). Each address is parsed against the email-address syntax rules. Typos like
john@@gmail.comoruser@.comare flagged instantly. - 2. Domain MX-record lookup. We query DNS for each domain's mail-exchange records. Domains without MX records can't receive email - so addresses on them bounce 100% of the time. Same technique you'd use with
dig MXon the command line, just at scale. - 3. Disposable-provider check. We maintain a 5,400+ domain blocklist of throwaway services (Mailinator, 10MinuteMail, Yopmail, Guerrillamail, TempMail, and ~5,000 more). The list is refreshed weekly from the open-source disposable-email-domains project.
- 4. Role-based filtering. Addresses like
admin@,support@,noreply@,postmaster@are shared inboxes - usually a bad target for cold outreach and often a sign of low engagement.
Why bulk-cleaning a list matters before you send
A high bounce rate ruins sender reputation faster than almost anything else. Gmail's bulk-sender requirements (Feb 2024) explicitly require a complaint rate under 0.3% and warn that "sending email to invalid addresses" is one of the fastest ways to land in spam folders. Yahoo's sender best-practices says the same. Both providers track bounce rates per sending domain and downgrade you silently.
In practical terms: an unverified 10,000-email list usually has 8–15% invalid addresses. Mailing them all in one campaign sends a 1,000-1,500 bounce signal to receiving ISPs. Two campaigns later your domain is in the spam folder for everyone - including the people who actually want to hear from you.
A 10-minute pre-send verification using a free tool like this one catches the obvious junk. For the rest (catch-all domains, deactivated mailboxes, spam traps) you need a live SMTP probe - which is what our paid product does.
When to use this free tool vs. paid verifier
Use the free tool when
- → You have under 10 addresses to sanity-check
- → You want to test how dirty a list is before paying to clean it
- → You're checking individual addresses or small batches manually
- → Cost matters more than catching every catch-all / spam trap
Use the paid verifier when
- → You're cleaning 100+ emails and care about deliverability
- → You need to catch catch-all domains and disabled mailboxes
- → You want segmented CSV output (valid / invalid / risky)
- → You want a programmatic API for signup-form verification
Frequently asked questions
Is this bulk email checker really free?
Yes - completely free, no signup required. Rate-limited to a small number per minute so we can keep it open to everyone.
How accurate is it without SMTP probe?
About 80%. Syntax + MX + disposable detection catches the obvious junk. For 99% accuracy on real campaigns, our paid SMTP-probe verifier opens an actual connection to the destination mail server and confirms the mailbox exists.
Why only 10 addresses per check?
Each check fires 10 DNS lookups in parallel against arbitrary domains. We cap the batch size so the tool stays free for everyone and bots cannot use us as a DNS amplification service.
Will recipients see I checked their email?
No. The free tool never sends any email. It only does DNS lookups, which destination servers do not see.
Can I download the results?
On this free page, results are displayed in the browser only. For CSV export segmented by status (valid / invalid / risky / catch-all / disposable / role-based), use the paid bulk verifier - first 100 emails are free on signup.