Public benchmark · updated in real time
Every competitor claims 99%. None publishes the methodology. We publish ours — the exact SQL, the exact sample size, the exact formulas — and split precision into three separately-defined numbers instead of collapsing them into one convenient headline.
Same underlying data, three published metrics. Pick which one honestly matches your workflow.
found / total
Email confirmed via SMTP RCPT-TO handshake with the destination server. Most conservative. Matches the definition independent auditors use in category comparisons.
(found + protected) / total
Includes M365/Proofpoint/Mimecast domains that accept our probe but don't confirm existence. Matches how every enterprise vendor implicitly reports.
found / (found + protected + catch_all)
Precision on the subset we chose to return. This is the same shape most category headline claims are computed on — precision only against the emails a vendor chose to return, not against the full input list.
found, protected, catch_all,not_found, no_mx, deferred, error.SELECT status, COUNT(*) FROM leads WHERE status NOT IN (NULL, 'pending') GROUP BY statusEvery published category headline (typically 95–99%) is subset-precision on the emails a vendor chose to return. Independent whole-list audits by third-party researchers put effective precision far lower than the headline once the denominator includes the full input list — which is why we publish three separately-defined numbers instead of one.
| Vendor | Claim | Independent audit | Coverage |
|---|---|---|---|
| Category headline (typical) | 95–99% | subset-only | — |
| Category same-methodology (typical) | — | varies by list | — |
| Coalstoke | Segmented (three numbers, no headline) | Self, live, above | Above |
Precise vendor-by-vendor numbers vary week to week and by input sample. Rather than freeze fabricated audit numbers into a comparison table, we publish our own three metrics live and invite direct head-to-head runs. Bring your own list and API keys — the numbers we return are reproducible.
Same 15 leads, three engines. Pulled at random from the 3,400-lead D1 sample — no cherry-picking. Sample size is small so treat this as directional, not a leaderboard. The point is showing where each engine wins and where a combined waterfall outperforms any single provider.
| Engine | Verified | Email returned | Cost / verified |
|---|---|---|---|
| Coalstoke SMTP only | 8 / 15 (53%) | 13 / 15 (87%) | $0.004 |
| Hunter API only | 8 / 15 (53%) | 10 / 15 (67%) | ~$0.05 rack |
| Icypeas API only (projected) | ~7 / 15 | ~9 / 15 | ~$0.02 rack |
| Coalstoke + Hunter BYOK fallback | 12 / 15 (80%) | 13 / 15 (87%) | ~$0.03 |
| + Icypeas as 3rd fallback (projected) | ~13 / 15 | 14 / 15 | ~$0.04 |
"Verified" = engine confirmed the email is deliverable via SMTP handshake or provider-side verification signal. "Email returned" includes probable-guess emails on catch-all and protected domains that no single-engine test could confirm. Icypeas row is projected from their published methodology pending API access.
Same benchmark, sliced by mail infrastructure. If your list is 90% Google Workspace, Hunter alone gets you most of the way. If it's a mixed enterprise list with heavy catch-all / Proofpoint / niche self-hosted, the combined waterfall pulls ahead by 25+ points.
| Mail infra | Best engine | Why |
|---|---|---|
| Google Workspace | Coalstoke SMTP + Hunter | SMTP RCPT works cleanly, Hunter has strong pattern data — nearly tied at 90%+. |
| Microsoft 365 (protected) | Combined waterfall | O365 accepts anything → we guess pattern, BYOK confirms via provider records. |
| Proofpoint / Mimecast | BYOK fallback (Hunter/Icypeas) | SMTP probe blocked at edge — provider records are the only signal. |
| Catch-all domains | Combined waterfall | SMTP says "accept" on everything — BYOK is the tiebreaker with real deliverability data. |
| Niche SME / self-hosted | Coalstoke SMTP alone | Small vendors aren't in most finders' scrape corpus — SMTP is the only shot. |
| Deep enterprise (Fortune 500) | Combined + human review | No engine hits 90%+ — SMTP probes rate-limited, pattern data is stale. Set expectations at 60–70%. |
Wholesale API pricing starts at $0.005 per verified at enterprise volume — undercuts every published API rack in the category while keeping your retail margin healthy. Attach behind your brand or take the full white-label stack at verify.yourbrand.com.
Starter
$0.015
< 10K / mo
Growth
$0.010
10K – 50K / mo
Scale
$0.007
50K – 250K / mo
Enterprise
$0.005
250K+ / mo
Want to run this benchmark against your own list? Sign up for 50 free credits — drop a CSV, get the four numbers back for your own data. That's the entire product.