One REST call returns a full 7-check email deliverability audit for any domain: MX, SPF, DKIM, DMARC, TLS, reverse-DNS, and blocklists, scored the same way the free audit and Pro monitoring are.
No SDK to install. Bearer auth, JSON in, JSON out. 100 audits/day on Pro, 500/day on Agency.
curl -H "Authorization: Bearer <your-api-key>" \ "https://inboxproof.email/api/v1/audit?domain=yourdomain.com"
Prefer the terminal? The free inboxproof-cli runs the same 7 checks locally and prints a 0-100 score with the exact record to fix. No account, no API key.
npx github:jtc268/inboxproof-cli yourdomain.com
/api/v1/audit?domain={domain}
| Auth | Authorization: Bearer <key> (or ?key=<key>) |
| domain | Required. The domain to audit, e.g. yourdomain.com |
| Rate limit | 100 audits/day on Pro · 500/day on Agency |
{
"ok": true,
"domain": "yourdomain.com",
"at": "2026-02-14T09:30:00.000Z",
"score": 82,
"grade": "B",
"checks": [
{ "id": "mx", "name": "MX & mail routing", "status": "pass" },
{ "id": "spf", "name": "SPF", "status": "pass" },
{ "id": "dkim", "name": "DKIM", "status": "warn" },
{ "id": "dmarc", "name": "DMARC", "status": "pass" },
{ "id": "tls", "name": "TLS", "status": "pass" },
{ "id": "ptr", "name": "Reverse DNS (PTR)", "status": "warn" },
{ "id": "rbl", "name": "Blocklists", "status": "pass" }
]
}
status is pass, warn, or fail. The score is the weighted sum (DMARC and MX carry the most), 0–100. The same engine powers the free audit and Pro daily monitoring.| 401 | Missing, invalid, or non-Pro API key. |
| 400 | Missing or malformed domain. |
| 429 | Rate limit exceeded for the day. |
Wire a daily deliverability check into your deploy pipeline, monitor client domains from your agency dashboard, or gate cold-email sends on a passing score.
Get Pro: $14.50/mo