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The AI Entrepreneur
The AI Entrepreneur

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From Domain Name to Company Intel: Building an Enrichment API With Zero External APIs

#tutorial

Give me a domain name. I'll give you the company's tech stack, social profiles, contact emails, WHOIS history, DNS records, and email provider — all from first principles, no Clearbit required.

The $99/Month Problem

Company enrichment APIs are everywhere. Clearbit, Apollo, ZoomInfo, Hunter.io. They charge $99-499/month. But most of that data is publicly available — in HTML, DNS records, WHOIS registration, and SSL certificates.

So I built my own. Zero external API calls. Just Node.js, DNS lookups, and clever HTML parsing.

What You Get From a Single Domain

enrichCompany("stripe.com") returns:

{
  "company_name": "Stripe",
  "technologies": ["React", "Next.js", "AWS", "Stripe", "Google Workspace"],
  "social_profiles": {
    "twitter": { "handle": "stripe" },
    "linkedin": { "handle": "stripe" },
    "github": { "handle": "stripe" }
  },
  "contact": { "emails": ["jane.diaz@stripe.com"] },
  "domain_info": { "age": "30y 6m", "registrar": "Safenames Ltd" },
  "dns": {
    "mx": ["aspmx.l.google.com"],
    "has_spf": true, "has_dmarc": true
  }
}
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6 data categories from 4 free sources.

Source 1: HTML (Tech Stack + Socials + Contacts)

Technology Detection

35+ technology patterns across 6 categories:

const TECH_PATTERNS = {
  'React': [/__NEXT_DATA__/i, /react/i, /_next\\//i],
  'Next.js': [/__NEXT_DATA__/i, /_next\\/static/i],
  'WordPress': [/wp-content/i, /wp-includes/i],
  'Shopify': [/cdn\\.shopify\\.com/i],
  'Google Analytics': [/google-analytics\\.com/i, /gtag\\(/i],
  'Cloudflare': [/cloudflare/i, /cf-ray/i],
  'HubSpot': [/hubspot\\.com/i, /hs-scripts/i],
  'Intercom': [/intercom\\.com/i],
  // ... 35+ total
};
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If Stripe's page loads a script from cdn.segment.com, we know they use Segment.

Social Profile Extraction

Regex patterns for 8 platforms catch links in headers, footers, and meta tags:

const SOCIAL_PATTERNS = {
  'twitter': /https?:\\/\\/(www\\.)?(twitter|x)\\.com\\/([a-zA-Z0-9_]+)/gi,
  'linkedin': /https?:\\/\\/(www\\.)?linkedin\\.com\\/(company|in)\\/([a-zA-Z0-9_-]+)/gi,
  'github': /https?:\\/\\/(www\\.)?github\\.com\\/([a-zA-Z0-9_-]+)/gi,
  // + facebook, instagram, youtube, tiktok, threads
};
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Source 2: DNS Records

Node.js built-in dns module — zero npm packages:

import dns from 'dns';
import { promisify } from 'util';
const resolveMx = promisify(dns.resolveMx);
const resolveTxt = promisify(dns.resolveTxt);
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Email Provider Detection from MX Records

This is my favorite trick. MX records reveal the email provider:

function detectEmailProvider(mxRecords) {
  const mx = mxRecords.join(' ').toLowerCase();
  if (mx.includes('google')) return 'Google Workspace';
  if (mx.includes('outlook') || mx.includes('microsoft')) return 'Microsoft 365';
  if (mx.includes('zoho')) return 'Zoho Mail';
  if (mx.includes('protonmail')) return 'ProtonMail';
  return 'Custom/Self-hosted';
}
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Stripe's MX → aspmx.l.google.com → Google Workspace. Useful for B2B sales teams.

SPF & DMARC Detection 

const txtRecords = await resolveTxt(domain);
const allTxt = txtRecords.flat().join(' ');
const has_spf = allTxt.includes('v=spf1');
const has_dmarc = allTxt.includes('v=DMARC1');
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Companies with SPF + DMARC will receive your outreach. Without? Spam folder.

Source 3: WHOIS

Domain age is a useful sales signal. 30-year-old domain = established company. 6-month-old = fresh startup.

Source 4: HTTP Headers

cf-ray header → Cloudflare. server: nginx → Nginx. x-powered-by: Express → Node.js.

Putting It Together

All sources run concurrently:

async function enrichCompany(domain) {
  const [html, dns, whois] = await Promise.allSettled([
    fetchAndParseHTML(domain),
    fetchDNSRecords(domain),
    fetchWHOIS(domain),
  ]);
  return { /* merged results */ };
}
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Total enrichment time: 2-4 seconds per domain.

The Numbers

Tested on 200 domains:

  • Tech detection accuracy: ~85% (vs BuiltWith)
  • Social profile extraction: ~90%
  • Email provider detection: ~95%
  • Average response: 3.1 seconds
  • Cost: $0.005 per domain

Price Comparison

This API Clearbit Hunter.io
Per enrichment $0.005 $0.099 $0.010
10K leads/month $50 $990 $100
API key required No Yes Yes
External API calls Zero N/A N/A

Same data categories, 20x cheaper than Clearbit.

Try It

🔗 Company Enrichment API on Apify
📦 Source on GitHub

One domain in, full company profile out. No API key, no subscription.

Also check out:

Built with Node.js, Cheerio, and the Apify SDK. Zero external API calls.

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