Verify catch-all and SEG-protected emails at 99.73% accuracy
Standard checks hit a catch-all or SEG-protected domain and hand back "catch-all." Our Advanced Catch-all Resolver goes further - Deep Verify mode runs multi-layer SMTP analysis and SEG signature detection to determine whether the mailbox is real, without sending a test email or waiting days for a bounce.
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100,000+ growing businesses rely on Clearout to verify leads every day
The catch-all problem
Somewhere between 40-60% of B2B emails sit behind a catch-all or SEG
A catch-all (or accept-all) domain accepts mail for any address, real or not. Add a Secure Email Gateway like Proofpoint, Mimecast, or Barracuda, and most verifiers give up entirely - leaving you to mail blind or quietly lose a huge slice of your addressable market.
of B2B email addresses sit on catch-all domains
higher bounce likelihood on unresolved catch-all sends
of a typical list gets marked "catch-all" by standard verifiers
mode switch (Deep Verify) to resolve most of it
How the industry actually does this
Four ways vendors try to resolve catch-alls - and what each one costs you
"Catch-all email verification" isn't one method. It's a category with real trade-offs, and most vendors only pick up one piece of it.
Send-and-wait (burner testing)
Sends a real or blank email to the address and watches for a bounce over 24-72 hours, since some bounces arrive days late.
+ Definitive- Slow, and sending puts your domain at risk
Identity-server cross-referencing
Checks the address against enterprise identity systems rather than the mail server itself.
+ Fast- Can mismatch when identity and mailbox state drift apart
SEG behavior-pattern mapping
Maps the known response patterns of gateways like Proofpoint, Mimecast, and Barracuda, and infers status from how the gateway behaves instead of what it literally says.
+ Handles enterprise SEGs- Only as good as the pattern library behind it
Signal-only inference
Skips SMTP analysis and infers validity from external signals - pattern matching, historical data, web presence.
+ Fast, no sending- Weaker without protocol-level grounding
Advanced Catch-all Resolver - Deep Verify mode
Multi-layer SMTP analysis for protocol-level grounding, combined with SEG signature detection for the gateways that block standard checks - all without sending a message or waiting on a bounce.
No sending risk. No multi-day wait. No identity-server mismatch. A definitive Safe-to-Send verdict instead of a single guess.
Inside the Advanced Catch-all Resolver
How Deep Verify Resolves Catch-All Emails
"This domain is catch-all" is detection. "[email protected] is a real, deliverable mailbox" is resolution. Every verifier can do the first. Deep Verify is built to do the second.
Multi-layer SMTP analysis
Instead of reading just the final RCPT TO response, Deep Verify analyzes the full SMTP conversation - command timing, banner patterns, and response specificity - to spot the difference between a real mailbox and a blanket "accept everything" reply.
SEG signature detection
Deep Verify identifies Proofpoint, Mimecast, Barracuda, and Microsoft EOP by their SMTP signatures, then applies gateway-specific logic instead of taking a generic "250 OK" at face value.
A clear verdict, not a guess
Every resolved address gets a Safe-to-Send verdict - Yes, No, or Risky - alongside its Valid/Invalid status, so you know exactly which addresses are actually safe to mail, not just technically deliverable.
Zero test emails sent
Resolution happens entirely at the protocol and infrastructure level - nothing is ever sent to the address being verified, so your sender reputation stays untouched during the check itself.
Deep Verify recognizes gateway signatures from Proofpoint, Mimecast, Barracuda, and Microsoft EOP - then adjusts its analysis for each.
How we hold ourselves accountable
How we measure catch-all email verification accuracy
Most catch-all email checker tools lead with one accuracy number and stop there. We think the honest picture needs more than one metric, so this is what we measure Deep Verify against.
Resolution rate
% converted from catch-all to a conclusive result
How much of the "catch-all" pile actually gets resolved to Valid or Invalid, rather than staying ambiguous.
Valid recovery rate
Additional usable emails recovered
How many addresses move from "unusable" to "safe to send" - the net-new reach you get back.
False-positive rate
The metric that matters most
How often a "Valid" verdict turns out to be wrong. We treat this as the number that actually protects your domain.
Actual bounce rate
Real-world bounce rate on Safe/Valid
What happens when addresses we marked safe are actually mailed - not a lab number.
Unresolved rate
What we still can't determine
The honest remainder - addresses no method can safely resolve, reported plainly instead of hidden.
Cost & speed
Processing time and cost per 1,000 catch-alls
Deep resolution takes marginally longer than standard checks - still returned in seconds to minutes, not days.
Standard verification vs. Deep Verify mode
Why "catch-all detected" isn't the same as "catch-all resolved"
A lot of tools stop at the first column. Our Advanced Catch-all Resolver's Deep Verify mode is built for the second.
| Capability | Standard verification | Deep Verify Mode |
|---|---|---|
| Detects catch-all domains | ||
| Resolves catch-all to Valid/Invalid | ||
| Identifies specific SEG (Proofpoint, Mimecast, Barracuda) | - generic only | |
| Safe-to-Send verdict per address | ||
| No test emails sent | varies by vendor | |
| Bulk & real-time API | ||
| Time to result | Seconds - or days, if the method sends real emails and waits on bounces | Seconds to minutes |
| Risk to your sending domain during the check | None for protocol-based methods; real for send-and-wait methods | None - nothing is ever sent |
Use cases
Where the Advanced Catch-all Resolver earns its keep
Catch-all and SEG-protected domains show up most at exactly the accounts you most want to reach.
Stop losing enterprise contacts to "catch-all"
Enterprise domains are disproportionately catch-all and SEG-protected - exactly the accounts a cold outbound list can't afford to skip.
Clean a CRM full of corporate domains
Re-run existing CRM lists through Deep Verify to recover addresses that were marked unusable the first time they were checked.
Protect every client's domain, not just one
Run Deep Verify across every client account before a send - enterprise-heavy client lists are exactly where standard verification falls short.
Recover addressable market before a big send
Instead of suppressing every "catch-all" address before a campaign, resolve them first - most catch-all addresses are real, reachable inboxes.
WHAT CLIENT SAYS
Your Success, Our Proof.
Hayk Saakian
Logic Inbound, Co-founder
After trying Clearout, I almost never see any bounces or failed deliveries and our open rate is as high as 82% sometimes because the quality of our list is good now. The guaranteed deliverables features gives us a lot of confidence in Clearout as a product.
Deepak Shukla
Pearl Lemon, Founder & CEO
We as a lead generation agency were looking for a provider that could help us clean emails at scale. Clearout has proven to be an excellent resource to help us with that journey. Increasing our deliverability by 23%, it's now part of our go-to tool.
Paul Mendoza
SigParser, Co-founder
It works amazingly well at validating email addresses with great API and support. It was able to identify about 10% of the invalid contacts in our database. There are other products for email verification but Clearout by far has the best price and easiest to use.
Stop marking a third of your list "catch-all"
Sign up and run your first list through the Advanced Catch-all Resolver - see how much of your catch-all pile is actually reachable.
Start Verifying FreeFrequently Asked Questions
Want the fundamentals first? Read our guide on what catch-all emails are and how they affect deliverability, or explore the Advanced Catch-all Resolver alongside Clearout's CRM integrations for HubSpot, Salesforce, Zoho, GoHighLevel, Apollo, and many more.