How to Extract Emails from Any Website — Node.js Guide

#javascript #webdev #node #tutorial

Need to find email addresses on a website? Here is a clean approach using regex patterns and DNS validation.

The Approach

Most email extraction tools just use a simple regex. But for production use, you need:

Multiple regex patterns to catch different email formats
DNS MX record validation to verify the domain exists
Filtering out false positives (image filenames, CSS classes)
Deduplication

The Regex

const EMAIL_REGEX = /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g;

This catches 99% of email formats. But raw results need cleaning:

function cleanEmails(rawEmails) {
  return [...new Set(rawEmails)]
    .map(e => e.toLowerCase().trim())
    .filter(e => !e.endsWith(".png"))
    .filter(e => !e.endsWith(".jpg"))
    .filter(e => !e.includes("example.com"));
}

MX Record Validation

import dns from "dns/promises";

async function validateDomain(domain) {
  try {
    const mx = await dns.resolveMx(domain);
    return mx.length > 0;
  } catch {
    return false;
  }
}

Provider Detection

function detectProvider(mxRecords) {
  if (mxRecords.some(r => r.exchange.includes("google"))) return "Google Workspace";
  if (mxRecords.some(r => r.exchange.includes("outlook"))) return "Microsoft 365";
  if (mxRecords.some(r => r.exchange.includes("protonmail"))) return "ProtonMail";
  return null;
}