Most tools measure the easy case.
A simple mailbox check already gets that right. It goes to zero on the hard case — the one that decides whether verification was worth paying for at all.
That’s the number below, and it’s the one every incumbent’s marketing page skips.
share of B2B addresses on catch-all domains
— MailerCheck’s own 33,000-list study
Vendor-reported benchmarks.
Vendor-published, not independent audits.
Top accuracy score among 15 verifiers
Hunter's own 3,000-email test, itself included
ZeroBounce false-positive rate on catch-all addresses
Allegrow's own 1,222-email test. Missed 30% of real contacts
Accuracy targets by segment.
Targets, not measured results. Measured results appear under Live once enough outcomes are in.
| Segment | Target accuracy | Difficulty |
|---|---|---|
| Non-catch-all (standard SMTP) | ≥ 99% | |
| Enterprise tenant catch-all | ≥ 95% | |
| Google Workspace catch-all | 75–85% | |
| Generic SMTP catch-all | 65–80% | |
| SEG-fronted (Proofpoint/Mimecast) | 60–75% |
Feature comparison.
Checked against public vendor docs, Sept 2026 — not an independent audit.
| Feature | skink | ZeroBounce | NeverBounce | Kickbox | BriteVerify |
|---|---|---|---|---|---|
| Catch-all resolution1 | resolved if confident | included, standard | accept-all | risky | accept-all |
| Microsoft 365 check | resolved | resolved | not supported | not supported | not supported |
| Google Workspace catch-all | probabilistic | resolved (binary) | not supported | not supported | not supported |
| SEG handling | resolved | Silent unknown | Silent unknown | Silent unknown | Silent unknown |
| Greylisting2 | auto-retry | not supported | some | supported | partial |
| Confidence score | confidence score | paid add-on | binary | Sendex score | binary |
| Exposed reasoning | Reasons + signals | not supported | not supported | not supported | not supported |
| Credits never expire3 | forever | 2yr (new) | 12mo | 12mo | 12mo |
Hover any icon for detail.
1 Catch-all resolution: ZeroBounce's July 2026 update resolves many Microsoft 365 and Google Workspace catch-alls during standard validation — no longer a separate paid step.
2 Greylisting: Detected automatically — set allow_async_followup to retry in the background once the greylist window passes.
3 Credits never expire: ZeroBounce applies a 2-year expiry to new signups; pre-June-2026 customers keep no-expiry terms.
See it on your own list before you spend anything.
Start free — 100 credits