Evidence behind every verdict. Even the catch-alls.
No credit card. 100 free verifications — credits never expire.
{
"status": "deliverable",
"confidence": 0.96,
"safe_to_send": true,
"disposable": false,
"recommendation": "send"
}Example response — verify a real address above.
3 free verifications/day, no signup required
Recognizes 29 mailbox providers and 7 SEGs. See the list ↓
How we measure accuracy.
curl -s https://api.skink.dev/v1/verify \
-H "Authorization: Bearer $SKINK_API_KEY" \
-H "Content-Type: application/json" \
-d '{"email":"jane.doe@acme.com"}'{
"email": "jane.doe@acme.com",
"status": "deliverable",
"confidence": 0.91,
"signals": {
"reasons": [
"SMTP accepted (250)",
"Additional verification checks resolved mailbox existence"
]
},
"recommendation": "send",
"safe_to_send": true,
"disposable": false
}No SDK required — plain HTTPS in, JSON out. Node, Python, and Ruby SDKs are available if you’d rather.
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-confirms on resolved catch-alls in our own controlled test — skink's own ground-truth test — see /accuracy
Five things incumbents get wrong.
Protected inboxes, still resolved
Resolves inboxes behind SEGs where others just return unknown.
Exposed reasoning
signals.reasons on every result. Never just a code.
One score, not a coin flip
Confidence built from SMTP, provider, and recipient signals.
Honest, not manufactured
No forced proxies. Uncertainty is labeled — catch-alls say so, never laundered into deliverable.
Parked isn't always dead
We check if it forwards before calling it invalid.
How we compare.
Checked against public vendor docs, Sept 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.
Running 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.
Your email list is never our product.
Encrypted, always
Readable by default — one toggle switches to hash-only.
AES-256-GCM at rest; hashed mode uses keyed HMAC-SHA256.
365 days, by default
Retention is yours to set, not ours.
Adjustable anywhere from 1 to 365 days.
Never sold
We verify the list and stop there.
No resale. No enrichment. No ad use.
FAQ
Yes — readable in your history, encrypted at rest. One toggle in Settings switches to hashed-only storage. Records auto-delete on your schedule — 365 days by default, adjustable down to 1.
Never. We verify the list, return the verdicts, and stop there — no selling, no sharing, no enrichment. Your data stays yours.
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 combines SMTP, provider, and recipient-specific signals into one score — not a static model, 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.
Both. Upload a CSV for bulk list cleaning, or connect Claude/Cursor via our MCP server — same API underneath.