Building a WHOIS & DNS Lookup Tool: Domain Intelligence in One API Call

#python #webdev #automation

Why Domain Intelligence Matters

Whether you're doing security research, monitoring your own infrastructure, or evaluating a potential acquisition target, domain data tells a story. WHOIS records reveal ownership history. DNS records expose infrastructure topology. SPF/DMARC configs show email security posture.

The problem? Gathering all this data usually means jumping between multiple tools — whois CLI, dig, nslookup, online MX lookup tools... It's tedious and doesn't scale.

So I built a WHOIS & DNS Lookup Tool on Apify that returns everything in a single API call.

What It Does

Give it a domain (or a list of domains), and you get:

WHOIS Data: Registrar, creation date, expiration date, registrant info, status flags
DNS Records: A, AAAA, MX, NS, TXT, CNAME, SOA, CAA, SRV
Email Security: SPF and DMARC record detection
IP Resolution: Quick A-record IP lookup

All in clean, structured JSON.

Example Output

{
  "domain": "example.com",
  "whois": {
    "registrar": "RESERVED-Internet Assigned Numbers Authority",
    "creationDate": "1995-08-14",
    "expirationDate": "2026-08-13",
    "nameServers": ["a.iana-servers.net", "b.iana-servers.net"]
  },
  "dns": {
    "A": ["93.184.216.34"],
    "MX": ["0 ."],
    "TXT": ["v=spf1 -all"],
    "SOA": ["ns.icann.org. noc.icann.org. 2025081403 7200 3600 1209600 3600"]
  },
  "security": {
    "spf": "v=spf1 -all",
    "dmarc": "v=DMARC1;p=reject;sp=reject;adkim=s;aspf=s"
  },
  "resolvedIP": "93.184.216.34"
}

How It Works

The tool uses two battle-tested Python libraries:

python-whois for WHOIS registration data
dnspython for DNS record resolution

It wraps them in the Apify SDK for cloud execution, automatic dataset storage, and pay-per-event pricing.

SPF/DMARC Detection

Email security is often overlooked in domain analysis. The tool checks TXT records for SPF policies and queries _dmarc.{domain} for DMARC configurations — two critical indicators of email deliverability posture.

Use Cases

Scenario	What You Get
Security Audit	Full DNS topology + WHOIS ownership trail
Domain Monitoring	Track expiry dates and DNS changes over time
Email Deliverability	SPF/DMARC validation for sender domains
Competitive Intel	Infrastructure discovery via DNS records
SEO Analysis	Name server patterns, CDN detection