Case Study

Wise Squad

Outbound systems for B2B companies and agencies.
Method: Clay waterfall enrichment. Emails verified: 5,000+

“The biggest value isn’t just verification accuracy — it’s recovering contacts that would otherwise stay unused.”

“Today, Filtrat is my default email verification solution. When you’re running outbound through Clay and waterfall enrichment, every additional verified email matters, and an extra 15% of reachable prospects can make a noticeable difference in campaign performance.”

Artem Matsa

Founder, Wise Squad

Background

The Setup

The team builds outbound systems for B2B companies and agencies. The lead generation workflow runs through Clay with waterfall enrichment — every additional verified email directly translates into more opportunities for their clients.

For a long time the stack included NeverBounce alongside several other providers for email verification. Standard verifications worked well. But catch-all domains almost always remained unresolved — and nobody questioned it because that’s what every tool did.

The Problem

15-20% of Every List — Unusable

At scale, unresolved catch-all emails represent a significant portion of any lead list. Most verification providers return them as “unknown” and move on. Two bad options follow: skip them and lose the contacts, or email them blind and risk bounces.

Typical lead list before filtrat

Verified (sendable): ~80%

Catch-all / unknown (skipped): ~17%

Invalid (removed): ~3%

Skip them

Lose 15-20% of potentially valid contacts

Email them blind

Risk bounces and sender reputation damage

The 15-20% catch-all segment was treated as a cost of doing business. Nobody expected those contacts to become usable.

The Switch

One Capability Changed Everything

After several months and 5,000+ email verifications, the difference became obvious. On the exact same lead lists, filtrat consistently resolved catch-all emails that the previous stack left as unknown.

Results

The Numbers

+0%

More verified contacts from the same lists

Email verifications processed

Tool instead of combining multiple providers

Catch-all recovered

Previously unusable emails now safe to include

Unexpected Finding

Catch-All Contacts May Be Better Leads

Catch-all addresses often generated healthy reply rates. The working theory: these inboxes receive less outbound traffic than typical business emails because everyone else’s verification tool told them to skip.

“Catch-all inboxes receive less cold outreach because every other tool tells you to skip them. Less competition = higher reply rates.”

Segmenting catch-all contacts into dedicated campaigns is being tested further — early indicators suggest they outperform standard verified contacts on engagement.

Stack Change

From Multiple Providers to One

Before

NeverBounce for primary verification

Additional providers for coverage

Catch-all returned as "unknown" across all tools

15-20% of every list discarded

With Filtrat

One provider for verification + catch-all resolution

Same lead lists, 15% more verified contacts

Catch-all resolved to definitive status

Recovered contacts included in campaigns with healthy reply rates

Summary

Key Numbers

Emails verified	5,000+
Additional verified contacts	+15% from same lists
Catch-all recovery	Previously 0%, now resolved
Providers replaced	Multiple consolidated to one
Catch-all reply rate	Healthy — less saturated inboxes
Time using filtrat	Several months
Status	Default verification provider

Bottom Line

Takeaway

The switch wasn’t about replacing a broken tool — NeverBounce worked fine for standard verifications. The switch was about recovering the 15% of every list that every tool left on the table.

When outbound runs through Clay with waterfall enrichment, every additional verified email is another shot at a meeting. An extra 15% of reachable prospects from the same data, at the same sourcing cost, without adding complexity — that’s what made filtrat the default.

The unexpected bonus: catch-all contacts may actually be better leads because fewer competitors can reach them.

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