u/Top_Bodybuilder_5833

Been doing a lot of B2B list verification lately and something about how people treat the results bugs me. Curious if others see it the same way.

With B2B, a huge chunk of your list sits on company domains, and a lot of those are catch-all (the server accepts mail for any address, so a verifier can't actually confirm the specific mailbox exists). So you run a B2B list and get this big pile of "risky / catch-all / unknown" that a consumer list just wouldn't have.

What I see most people do is treat catch-all like it's basically invalid and cut them. But a catch-all flag doesn't mean the person is fake. It means their mail server won't tell you either way. On B2B that's often your actual target accounts, Google Workspace setups especially.

How I've landed on handling it:

• Hard invalids get deleted, no question. Those are the ones that actually bounce and hurt you.
• Catch-all/risky I don't auto-delete. I'll send, but I keep them in their own segment so a rough batch doesn't blend into my main sending reputation.
• If a catch-all address never engages after a couple of touches, then it's gone.

Basically on B2B the "risky" bucket is where all the judgment is, not the invalid one.

Quick disclosure since it's relevant: I run a small verification tool, so I stare at these results way too much, which is why I have opinions on it. Not plugging anything, I actually want to know:

How are you all treating catch-all on B2B sends? Send anyway, segment them off, or drop them? Feels like everyone does this differently and I've never seen a consensus.

Disclosure first so I don't get removed: I run a small email verification tool (Sealch), so obviously I'm biased toward verifying in general. Not selling anything in this post though. This is just the thing I wish more people got before they "clean" a list, because it quietly costs them subscribers who actually opted in.

Run a list through any verifier and you get three buckets:

Valid. Mailbox confirmed, keep them.

Invalid. The server literally said the mailbox doesn't exist. Delete these, no debate. Sending to them = hard bounces, and hard bounces are what actually trash your sender reputation.

Catch-all / risky / unknown. This is the one people get wrong.

A catch-all domain accepts mail for any address, so the verifier physically can't tell if that specific mailbox exists. Loads of company domains and Google Workspace setups are catch-all. So a bunch of your real, opted-in people on their work email get flagged "risky," not because they're fake but because their server won't confirm either way.

Then people see "risky," get nervous, and delete the whole bucket. If those folks opted in, you just deleted engaged subscribers over a technical quirk.

What I'd actually do with a permission list:

1. Kill the invalids. Always.
2. Keep any risky/catch-all person who's opened or clicked recently. They said yes and they're active. Catch-all isn't a reason to cut them.
3. Risky people who've gone quiet 6+ months? Treat them like any dead weight. One re-engagement email, sunset if nothing. Same as you'd do anyway.
4. Only verify at import and before big or re-engagement sends. Verifying the whole list every send is a waste of money and fixes nothing. Your daily deliverability problem is engagement, not new invalids appearing out of nowhere.

Bottom line, bounces come from invalids and dead mailboxes, not from catch-all people who engage. Delete the wrong bucket and you just shrink your list and your revenue for no deliverability gain.

Can get into how the SMTP check actually works if anyone wants the nerdy version.

Quick one for the agencies here.

I built an email verifier (Sealch) because paying ZeroBounce/NeverBounce 8 bucks per 1k felt ridiculous for what it actually is, a live SMTP check plus catch-all detection.

Mine runs the same check for $0.35 per 1k. And you don't get charged for the unknowns it can't confirm (protected/greylisted servers), which is where the big tools quietly pad the bill.

If you're verifying scraped or sourced leads before you hand them to a client or drop them into a sender, you're realistically overpaying like 90% for the identical result.

First 1k is free, no card. Honestly the best test is to take a list you already cleaned somewhere else and run it through mine to compare side by side.

DM me or it's in my profile. If you're pushing real volume every month I'll sort you out with custom pricing.

About 6 months ago I was cleaning an email list and looked at what the popular verification tools charge. ZeroBounce, NeverBounce, all of them sit around $8 per 1,000 emails. And when you actually look at what they do, it's a live SMTP check plus catch-all detection. Solid, but not eight-dollars-worth-of-magic solid.

What bugged me is the cost to actually run that check isn't anywhere near $8 per 1,000. They're just enterprise-priced tools everyone pays because they're the defaults. So I figured, what if someone did the exact same verification but priced it honestly.

That became Sealch. Same live SMTP handshake, same catch-all detection, 99.2% accuracy, but $0.35 per 1,000 instead of $8. Roughly a 20x price difference for the same core result.

It's been a grind. Solo and bootstrapped. Built the whole verification engine myself (SMTP checks, proxy rotation so I don't get blocked, concurrency handling so big lists don't crawl), plus the dashboard, billing, all of it. Put a ton into SEO and content too. The site does 100k+ pageviews a month now, which honestly surprised me.

Where I'm at: around $500 MRR, real paying customers, growing slowly. And the honest struggle right now isn't traffic, it's conversion. Lots of visitors, fewer signups than I'd like. That's the wall I'm chipping at.

Sharing it as part of the journey. If you run cold email or clean lists and you're tired of paying enterprise prices to verify, it's Sealch (sealch .com), first 100 verifications a day are free for a week so you can just try it. And if you've cracked the visitors-to-signups problem on a tool like this, I'd genuinely love any advice. That's my current bottleneck.

About 6 months ago I was cleaning an email list and looked at what the popular verification tools charge. ZeroBounce, NeverBounce, all of them sit around $8 per 1,000 emails. And when you actually look at what they do, it's a live SMTP check plus catch-all detection. Solid, but not eight-dollars-worth-of-magic solid.

What bugged me is the cost to actually run that check isn't anywhere near $8 per 1,000. They're just enterprise-priced tools everyone pays because they're the defaults. So I figured, what if someone did the exact same verification but priced it honestly.

That became Sealch. Same live SMTP handshake, same catch-all detection, 99.2% accuracy, but $0.35 per 1,000 instead of $8. Roughly a 20x price difference for the same core result.

It's been a grind. Solo and bootstrapped. Built the whole verification engine myself (SMTP checks, proxy rotation so I don't get blocked, concurrency handling so big lists don't crawl), plus the dashboard, billing, all of it. Put a ton into SEO and content too. The site does 100k+ pageviews a month now, which honestly surprised me.

Where I'm at: around $500 MRR, real paying customers, growing slowly. And the honest struggle right now isn't traffic, it's conversion. Lots of visitors, fewer signups than I'd like. That's the wall I'm chipping at.

Sharing it as part of the journey. If you run cold email or clean lists and you're tired of paying enterprise prices to verify, it's Sealch (sealch.com), first 100 verifications a day are free for a week so you can just try it. And if you've cracked the visitors-to-signups problem on a tool like this, I'd genuinely love any advice. That's my current bottleneck.