API reference

First verify in under 5 minutes.

curl -s https://api.skink.dev/v1/verify \
  -H "Authorization: Bearer $SKINK_KEY" \
  -d '{"email":"jane@acme.com"}'

{ "status": "deliverable", "confidence": 0.91 }

01 — setup

Get a key.

Server-side only — a leaked key spends your credits. If exposed, revoke it from the dashboard.

02 — request

Verify.

One POST, two headers, a JSON body — pick your language, that’s the whole integration.

curl -s https://api.skink.dev/v1/verify \
  -H "Authorization: Bearer $SKINK_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email":"jane.doe@acme.com"}'

03 — response

Read the result.

{
  "email": "jane.doe@acme.com",
  "status": "deliverable",
  "sub_status": "catchall_resolved_exists",
  "confidence": 0.91,
  "accept_all": true,
  "mx_provider": "microsoft365",
  "signals": {
    "is_catchall": true,
    "catchall_resolution": "verified",
    "reasons": [
      "SMTP accepted (250)",
      "Catch-all domain — SMTP alone cannot determine individual mailbox existence",
      "Additional verification checks resolved mailbox existence"
    ]
  },
  "recommendation": "send"
}

signals.reasons explains why — including how a catch-all verdict was reached.

04 — reference

Status reference.

status	meaning
deliverable	Safe to send.
undeliverable	Hard bounce — don't send.
risky	Role address, full mailbox, or an unresolved catch-all.
unknown	Couldn't determine a verdict (timeout, greylist, DNS failure).

sub_status values (stable keys for parsing — signals.reasons is the human-readable version):

catchall_resolvedcatchall_uncertainprobe_inconclusiveno_mxinvalid_mailboxmailbox_fulldisposablegreylist_timeoutdns_failuresmtp_throttledsyntax_error

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