DKIM Check

What It Does

Tests 30+ common DKIM selectors (google, default, selector1, selector2, k1, s1, s2, mail, dkim, zoho, fm1, fm2, fm3, mimecast, proofpoint, mandrill, ses, smtpapi, sf1, sf2, hs1, hs2, pm, etc.) by querying <selector>._domainkey.<domain> TXT records. For each discovered key, validates the DKIM record format (v=DKIM1), identifies the key algorithm (k=rsa or k=ed25519 per RFC 8463), estimates key length (RSA key lengths are estimated from base64-encoded public key size; Ed25519 keys are always exactly 256 bits), parses hash algorithms (h= tag), service type (s= tag), and testing flags (t=y), detects revoked keys (empty p= tag indicating key rotation), warns about multiple DKIM records at the same selector, and identifies dual-signing setups. Returns a security score (0-100) with recommendations for key strength, rotation practices, and migration to Ed25519.

Why It's Useful

DKIM provides cryptographic proof that an email hasn't been modified in transit (RFC 6376). It's required for DMARC alignment and directly impacts email deliverability. RSA 1024-bit keys are now considered weak per RFC 8301 — 2048-bit RSA is the industry standard minimum, with Ed25519 (RFC 8463) as the recommended next-generation algorithm. Google, Yahoo, and Microsoft mandate DKIM signing for bulk senders (5,000+ emails/day) as of 2024-2025. Selector discovery also reveals which email services a domain uses — valuable for security assessments and competitive intelligence.

Use Cases

Parameters

Response Fields

Code Examples

curl "https://api.edgedns.dev/v1/security/dkim" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d "domain=google.com"

const response = await fetch(
  'https://api.edgedns.dev/v1/security/dkim?domain=google.com',
  {
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY'
    }
  }
);

const data = await response.json();
console.log(data);

import requests

response = requests.get(
    'https://api.edgedns.dev/v1/security/dkim',
    headers={'Authorization': 'Bearer YOUR_API_KEY'},
    params={
    'domain': 'google.com'
    }
)

data = response.json()
print(data)

Related Endpoints

External References

Learn more about the standards and protocols behind this endpoint.