BounceBan vs ZeroBounce: which actually resolves catch-all emails?

Q: Does ZeroBounce verify catch-all emails?

No. Per ZeroBounce's own status codes documentation, the catch-all status is defined as "These emails are impossible to validate without sending a real email and waiting for a bounce." ZeroBounce returns this status and does not attempt mailbox-level verification of those addresses. A small subset of well-known catch-all domains sits on their accept_all allow-list and is returned as effectively valid; everything else is flagged and deferred.

Q: What does accept_all mean in ZeroBounce?

accept_all is a status ZeroBounce returns for addresses on domains they have historically observed delivering successfully. From their docs: "These addresses belong to domains on the ZeroBounce accept_all list. The destination mail server is configured to accept any recipient and never issue an SMTP bounce." Treated as effectively valid by most downstream systems. Distinct from catch-all, which covers domains not on that allow-list.

BounceBan and ZeroBounce solve different problems on catch-all emails. ZeroBounce returns a catch-all status and, in their own documentation, explicitly does not attempt mailbox-level verification of those addresses. BounceBan attempts that verification and claims 85-95% reliable resolution on catch-all, greylisted, and SEG-protected emails. The two tools look superficially similar, but on a catch-all-heavy list you'll get very different results.

This post walks through that structural difference, what each tool actually does on a catch-all address, and what we found when we ran a real-world bounce dataset through both methodologies.

The structural difference: flag vs verify

The single most important thing to understand before picking between these two products is that they treat catch-all domains differently by design.

ZeroBounce returns one of six status codes. Two of them are relevant here, from ZeroBounce's own status-codes documentation:

catch-all: "These emails are impossible to validate without sending a real email and waiting for a bounce. 'Catch-all' means that the email server tells you that the email is valid, whether it's valid or invalid."

accept_all: "These addresses belong to domains on the ZeroBounce accept_all list. The destination mail server is configured to accept any recipient and never issue an SMTP bounce."

The distinction is operational. accept_all is a small allow-list of well-known domains ZeroBounce has historically observed delivering successfully, and those are returned as effectively valid. Everything else on a catch-all domain comes back as catch-all, which ZeroBounce themselves describe as impossible to validate without actually sending mail.

BounceBan takes the opposite position. From their landing page:

"BounceBan can reliably verify the true deliverability for 85～95% of emails that are catch-all, greylisted, or protected by SEGs."

And from their pricing page: "97%+ accuracy in real-time." Their methodology page describes proprietary algorithms that "verify all without sending an email" by probing mail server behaviour beyond the standard SMTP handshake.

Concretely, on a hypothetical catch-all address like [email protected] where acmecorp.com accepts everything:

	BounceBan	ZeroBounce
Returns	`valid` or `invalid` after probing	`catch-all` (no verification attempted)
Claimed accuracy on catch-alls	85-95% reliable resolution	Not applicable; not attempted
Headline accuracy claim	97%+ overall	99% overall (catch-alls excluded from the verified population)
Pricing model	Pay-as-you-go credits, 15% off on subscription	Pay-as-you-go credits and subscription
Credit expiry	Rollover, no expiry	Expire on subscription cancellation

The 99% accuracy figure ZeroBounce publishes is on the population of emails they actually classify as valid or invalid. Catch-all addresses sit outside that population. The 97%+ BounceBan publishes is across all addresses including catch-alls. They are not directly comparable headline numbers, even though they look like they should be.

What this means for your list

How much this matters depends on what share of your list lives on catch-all domains. DeBounce report that 10-30% of all emails are catch-all, and the share trends higher on B2B lists where most companies sit behind enterprise mail security gateways. Office 365 tenants, Google Workspace domains, and any organisation running Mimecast, Proofpoint, or Barracuda in front of their mail server typically present as catch-all to a verifier.

If 20% of your list is catch-all and your validator flags those as risky or catch-all and refuses to verify them, you have two bad options: drop the 20% and lose reachable prospects, or include the 20% and raise bounce rates. A tool that resolves a meaningful share of those addresses turns that 20% from a liability into an asset.

This is the trade space BounceBan and ZeroBounce are in. They are not competing on the same dimension.

BounceBan: how it works and what to expect

BounceBan is a catch-all specialist. Their core claim is that their probing methodology can resolve 85-95% of addresses on catch-all, greylisted, or SEG-protected domains to a definitive valid or invalid without sending an email. They explicitly support Office 365, Google Workspace, Mimecast, Proofpoint, and Barracuda, which together cover most of the inbound mail security gateways you will see in a B2B outreach list.

Pricing is credit-based with tiered packs from 10,000 to 1 million credits, custom plans above that. One credit per verification. They offer pay-as-you-go and monthly subscription (15% cheaper). Credits roll over and do not expire on standard pay-as-you-go plans. Free single email verifications without consuming credits, useful for ad-hoc testing.

Where BounceBan is weaker:

Methodology is closed. They describe their probing as proprietary but do not publish the specific mail server signals they inspect. You have to take the accuracy claim on trust unless you benchmark it yourself.
No bundled deliverability suite. ZeroBounce includes blacklist monitoring, an email finder, AI scoring, an inbox tester, and 40+ native integrations. BounceBan focuses on verification and verification only. If you want one vendor for verification plus warmup plus inbox testing, BounceBan is not it.
Smaller scale and shorter track record than ZeroBounce.

The strength is the singular focus on the problem most validators avoid.

ZeroBounce: the full-suite alternative

ZeroBounce has a 300,000+ customer base, a long operating history, and a verification result taxonomy with six statuses (valid, accept_all, catch-all, invalid, unknown, do_not_mail). They handle clean valid/invalid identification very well, and that is most of the work on most lists.

The deliverability suite is what differentiates them from a pure verifier. Their platform includes:

Blacklist monitoring across major RBLs
Email finder (find addresses by name and domain)
Inbox tester for placement diagnostics
AI activity-data scoring
40+ native integrations including Mailchimp, HubSpot, Klaviyo

For a team that wants one bill and one login for the broader deliverability problem, ZeroBounce is a reasonable consolidation play.

Where ZeroBounce is weaker:

The catch-all blind spot, explicit in their own docs.
Per-email pricing is steeper than budget verifiers like MillionVerifier or BounceBan at small to mid volumes.
Credit handling is tied to subscriptions; pause your subscription and unused credits are not always preserved the way pay-as-you-go credits are.

If your list is mostly clean valid/invalid with relatively few catch-all domains, ZeroBounce's broader suite is genuinely useful and the catch-all gap is an acceptable trade. If your list is catch-all heavy, that gap is the whole game.

Head-to-head: 538 real bounces from The Deal Lab

The most defensible way to compare validators is to run them on a known-bad dataset and measure what they catch. Synthetic test addresses, list rentals, and seed lists all introduce bias. We ran the test on a real one.

Methodology. Grant Beckmann, a GTM Engineer at The Deal Lab, shared 538 confirmed hard bounces from his outreach campaigns. The Deal Lab runs prospects through Clay with multiple email verification providers stacked in the same workflow, which is the standard playbook for serious GTM agencies. Every one of those 538 addresses had been cleared as safe by that stack before being sent, and bounced anyway. We took the same 538 and ran each one through OrbiSearch and BounceBan ourselves. Two numbers come out of this test: how many bounces each validator correctly flagged as bad, and how many bounces each validator wrongly cleared as safe. We do not measure the inverse case (wrongly flagging a valid address as bad), because that would require a separate dataset of known-good addresses.

BounceBan on the 538: correctly flagged 94.6% as bad. Cleared 5.4% as safe; those addresses bounced.

ZeroBounce does not have a comparable single number on this dataset because, per the structural point above, ZeroBounce does not attempt mailbox-level verification on catch-all domains. The bulk of these 538 hard bounces are catch-all addresses by composition, and on those ZeroBounce returns the catch-all status that explicitly defers verification. Putting a single accuracy number on ZeroBounce against this dataset would be misleading. The honest read: ZeroBounce is solving a different problem on these addresses.

What the test reliably tells you: BounceBan, when re-run on a dataset of real-world bounces that had previously been cleared by another stack of validators, catches 94.6 out of every 100 of them. That is a meaningful, defensible number on the population that matters for cold outreach.

A third option: how OrbiSearch performs on the same test

OrbiSearch sits in the same methodology category as BounceBan: we attempt mailbox-level catch-all verification rather than flagging and deferring. We ran the same 538 bounces through our engine.

OrbiSearch on the 538: correctly flagged 96.3% as bad. Cleared 3.7% as safe; those addresses bounced.

That is 1.7 percentage points ahead of BounceBan on the catch rate, and roughly 31% fewer bounces wrongly cleared (3.7% vs 5.4%). Same dataset, same input, same methodology. The gap comes from how the probing is constructed and which signals are inspected.

Pricing is from $0.0002 per validation pay-as-you-go, with the same credit-rollover behaviour as BounceBan plus credits that never expire on any plan. Full deep comparison in our OrbiSearch vs BounceBan teardown, and the OrbiSearch vs ZeroBounce comparison covers the equivalent against ZeroBounce.

We are obviously not impartial here, but the methodology and the dataset are reproducible. If you have your own bounce log, run it through us and see.

Which one to pick

The decision is mostly about what your list looks like, not about which brand you prefer.

Pick BounceBan if your list is catch-all heavy, you do not need a broader deliverability suite, and you want a verifier whose entire product surface is focused on catch-all resolution. The 94.6% catch rate on real bounces is genuinely strong, and the credit-rollover pricing is friendly to bursty workloads.

Pick ZeroBounce if your list is mostly clean valid/invalid addresses (catch-all domains are a small share), you want one vendor for verification plus blacklist monitoring plus warmup plus inbox testing, and you value the established brand and 300,000+ customer track record. The catch-all gap is real but may not matter for your particular list composition.

Consider OrbiSearch if your list is catch-all heavy and the bounces wrongly cleared as safe matter to you, or if you want pay-as-you-go credits that never expire and pricing from $0.0002 per validation. Same methodology category as BounceBan, with a higher catch rate and fewer missed bounces on the dataset above.

None of these are bad tools. They are solving slightly different problems, and the right pick depends on which problem you have.

FAQ

Does ZeroBounce verify catch-all emails?

No. Per ZeroBounce's own status codes documentation, the catch-all status is defined as "These emails are impossible to validate without sending a real email and waiting for a bounce." ZeroBounce returns this status and does not attempt mailbox-level verification of those addresses. A small subset of well-known catch-all domains sits on their accept_all allow-list and is returned as effectively valid; everything else is flagged and deferred.

What does accept_all mean in ZeroBounce?

accept_all is a status ZeroBounce returns for addresses on domains they have historically observed delivering successfully. From their docs: "These addresses belong to domains on the ZeroBounce accept_all list. The destination mail server is configured to accept any recipient and never issue an SMTP bounce." Treated as effectively valid by most downstream systems. Distinct from catch-all, which covers domains not on that allow-list.

How accurate is BounceBan on catch-all emails?

BounceBan claims 85-95% reliable verification on catch-all, greylisted, and SEG-protected addresses, and 97%+ overall accuracy. On the 538-bounce dataset described above, BounceBan correctly flagged 94.6% of real-world bounces and wrongly cleared 5.4% as safe. The headline claim and the audit number agree closely.

Is BounceBan or ZeroBounce cheaper for high-volume lists?

For pure verification at volume, BounceBan tends to be cheaper. Their credit packs go up to 1 million with custom enterprise pricing above, credits roll over and do not expire on pay-as-you-go, and the 15% subscription discount applies on top. ZeroBounce's per-email pricing is higher at small to mid volumes; their bundled deliverability suite is part of what you are paying for. If you only need verification, BounceBan is the more cost-effective choice.

Which catch-all email verifier should I use?

If catch-all resolution is the core requirement: BounceBan or OrbiSearch, not ZeroBounce. Between BounceBan and OrbiSearch, the choice comes down to catch rate and pricing model. On the dataset above, BounceBan caught 94.6% of real bounces and wrongly cleared 5.4% as safe; OrbiSearch caught 96.3% and wrongly cleared 3.7%. ZeroBounce is the right choice when catch-all is a small share of your list and you want bundled deliverability tooling.

Methodology details

Dataset: 538 hard bounces from real outreach campaigns at The Deal Lab.
Source: Provided by Grant Beckmann, GTM Engineer at The Deal Lab.
Pre-condition: Every address had been cleared as safe by multiple email verification providers stacked together in The Deal Lab's Clay workflow before being sent. All bounced anyway.
Test: Each of the 538 addresses re-run through OrbiSearch and BounceBan after the bounces had occurred.
What was measured: Percentage of real-world bounces each validator correctly flagged as bad, and percentage wrongly cleared as safe.
What this does not measure: How often each validator wrongly flags a valid, deliverable address as bad. That assessment requires a separate dataset of known-good addresses.
Reproducibility: The same methodology applies to any bounce log. We are happy to run third-party datasets on request.

Per-validator results are also published on the OrbiSearch vs BounceBan page.

If you are choosing between these tools for a data platform pipeline or a Clay-based GTM workflow, the right answer is usually whichever methodology category fits your list composition. Compare OrbiSearch directly: vs BounceBan · vs ZeroBounce · see pricing.

Last updated: 18 May 2026.