Email Extractor

About Email Extractor

This email extractor uses regular expressions to scan text and identify email addresses matching standard format patterns. Results are automatically deduplicated, producing a clean list of unique email addresses for analysis, migration, or compliance workflows.

Email Regex Pattern Explained

The extraction pattern balances RFC compliance with practical coverage:

Pattern: /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/gi

Component breakdown:
┌─────────────────┬──────────────────────────────────────┐
│ [a-zA-Z0-9._%+-]+ │ Local part (before @)              │
│                 │ - Letters (a-z, A-Z)                 │
│                 │ - Digits (0-9)                       │
│                 │ - Dot, underscore, percent, plus, hyphen │
│ @               │ At symbol (required separator)       │
│ [a-zA-Z0-9.-]+  │ Domain name                          │
│                 │ - Letters, digits, dots, hyphens     │
│ \.              │ Literal dot before TLD               │
│ [a-zA-Z]{2,}    │ Top-level domain (minimum 2 letters) │
└─────────────────┴──────────────────────────────────────┘

Flags:
  g = global (find all matches, not just first)
  i = case insensitive (USER@ = user@)

Email Format Compliance Matrix

Extraction Algorithm

JavaScript Email Extraction Implementation:

function extractEmails(text) {
  // Step 1: Define regex pattern
  const pattern = /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/gi;

  // Step 2: Find all matches (returns array or null)
  const matches = text.match(pattern) || [];

  // Step 3: Deduplicate using Set
  const unique = Array.from(new Set(matches));

  // Step 4: Return results
  return unique;
}

// Usage example:
const text = "Contact [email protected] or [email protected]";
const emails = extractEmails(text);
console.log(emails); // ["[email protected]", "[email protected]"]

Common Use Cases

• Log Analysis: Extract contact emails from support logs, error reports, or audit trails
• Data Migration: Pull email addresses from unstructured text exports or legacy systems
• Lead Generation: Extract contact information from web pages, documents, or PDFs
• GDPR Compliance: Identify personal data (email addresses) in text for data audits and DSAR responses
• Research: Collect author emails from academic papers, articles, or conference proceedings
• Email Cleanup: Find and consolidate duplicate addresses across multiple sources
• Security Analysis: Extract sender/recipient emails from email headers or logs

Email Extraction Example

Input Text:
"Contact our team at [email protected] for assistance.
 You can also reach [email protected] or [email protected].
 For press inquiries, email [email protected] or [email protected] again.
 Alternative: admin subdomain at [email protected]"

Extraction Process:
  Match 1: [email protected]
  Match 2: [email protected]
  Match 3: [email protected]
  Match 4: [email protected]
  Match 5: [email protected] (duplicate)
  Match 6: [email protected]

Output (deduplicated, one per line):
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]

Total: 5 unique emails found

Extraction Limitations

• Format-only validation: Matches pattern, does not verify domain existence or mailbox validity
• No DNS/MX checks: Does not confirm the domain has mail servers
• Quoted strings: Does not match RFC 5322 quoted local parts ("john.doe"@example.com)
• International domains: Does not match IDN/UTF-8 characters (RFC 6531)
• Obfuscated emails: Does not detect "user at domain dot com" or similar obfuscation
• Case sensitivity: Deduplication is case-sensitive ([email protected] ≠ [email protected])

Email Validation vs Extraction

Deduplication with Set

JavaScript's Set data structure provides efficient O(n) deduplication:

// Set automatically removes duplicates
const emails = [
  "[email protected]",
  "[email protected]",
  "[email protected]",  // duplicate
  "[email protected]"
];

const uniqueSet = new Set(emails);
// Set(3) { "[email protected]", "[email protected]", "[email protected]" }

const uniqueArray = Array.from(uniqueSet);
// ["[email protected]", "[email protected]", "[email protected]"]

// Note: Set uses SameValueZero comparison
// "[email protected]" and "[email protected]" are different values
// For case-insensitive dedup, convert to lowercase first:
const lowercaseUnique = Array.from(
  new Set(emails.map(e => e.toLowerCase()))
);