Calibrated confidence for every address. Even the catch-alls.
No credit card. 100 free verifications — credits never expire.
{
"status": "deliverable",
"confidence": 0.96
}Example response — verify a real address above.
3 free verifications/day, no signup required
Recognizes 10 mailbox providers and 3 SEGs. See the list ↓
How we measure accuracy.
curl -s https://api.skink.dev/v1/verify \
-H "Authorization: Bearer $SKINK_KEY" \
-H "Content-Type: application/json" \
-d '{"email":"jane.doe@acme.com"}'{
"email": "jane.doe@acme.com",
"status": "deliverable",
"confidence": 0.91,
"reasons": [
"Address resolved with high confidence",
"Calibrated against real delivery outcomes"
],
"recommendation": "send"
}No SDK. Plain HTTPS in, JSON out.
share of B2B addresses on catch-all domains, no clean answer possible — MailerCheck's own 33,000-list study
top score among 15 verifiers tested — Hunter's own 3,000-email benchmark of itself vs. competitors
false-positive rate on unresolved addresses, 30% of real contacts missed — Allegrow's own 1,222-email test, ZeroBounce standard
false-confirm rate on fake mailboxes in our own controlled catch-all test — skink's own ground-truth test — see /accuracy
Why it wins.
Protected inboxes, still resolved
Security gateways silently return unknown
Resolves behind SEGs.
Exposed reasoning
No explanation for why an address was marked risky or invalid
reasons[] on every result — not just a code.
Calibration that never stops
Static thresholds that never adapt to your actual bounce data
Re-checked nightly against real delivery outcomes.
Honest, not manufactured
Some verifiers proxy-hop to force an answer out of a stalling server.
No forced proxies — a real risky beats a fake deliverable.
How we compare.
Checked against public vendor docs, July 2026 — not an independent audit. See /accuracy for the full competitor matrix.
Providers we support.
Buy a pack, use it whenever.
1 credit = 1 verification. Unknown results are free. SMTP checks and catch-all resolution included at every tier — no paid add-on.
100 credits, no card required — enough to see real accuracy on your own list before you spend anything.
10,000 credits
$0.0049 / email
Your first real batch. Validate a list before a campaign goes out.
Buy Growth200,000 credits
$0.003 / email
Built for teams running cold outreach at real throughput.
Buy Volume500,000 credits
$0.0026 / email
Established sending programs — half a million credits without jumping straight to Max.
Buy BusinessRunning past a few million verifications a month, or have other custom requirements? Talk to us before you buy another Max pack.
Save a card once. No subscription.
Your pack repurchases automatically.
Same price as buying it by hand.
One click in Billing.
FAQ
Not in readable form, by default — we keep the domain and a hashed version of the address, enough to filter and dedupe but not to read back. Need to look up exactly what you sent later? Turn on plaintext storage (encrypted at rest) in Settings. Either way, records auto-delete on a schedule you control — 7 days by default, up to 90.
No. It's included in every plan, not sold as a premium add-on.
They never expire. No forced subscription, no use-it-or-lose-it.
Higher means more certain. Confidence is recalibrated nightly against real delivery outcomes — not a static model frozen at launch, and not a vendor marketing percentage.
Detected automatically. Set allow_async_followup on your request and we'll retry in the background once the delay clears — poll for the upgraded result instead of re-submitting the address yourself.