email-finder（电子邮件查找器）

Email Finder

Overview

Discover email addresses associated with a domain using a hybrid approach: free methods first (web scraping, pattern guessing, WHOIS lookup), then APIs (Hunter.io, Apollo.io, etc.) when keys are available.

When to Use

• Scan a domain to find associated emails
• Find contact emails for a company
• Replace email hunter functionality
• Find email patterns for a domain
• Verify email addresses
• Enrich contact data with discovered emails

Project Context Discovery

Before finding emails:

1. Check for existing email discovery tools
2. Review available API keys (Hunter.io, Apollo.io)
3. Check compliance/privacy requirements
4. Look for project-specific [project]-email-finder skill

Methodology

Free Methods (Primary)

1. Web Scraping - Scan /contact, /about, /team pages for emails
2. WHOIS Lookup - Query domain registration data
3. Pattern Guessing - Generate patterns from names found on site:

- firstname.lastname@domain.com - firstnamelastname@domain.com - firstname@domain.com - f.lastname@domain.com

API Methods (If Keys Available)

Email Result Interface

interface EmailResult {
  email: string;
  source: 'web-scraping' | 'whois' | 'pattern-guessing' | 'hunter' | 'apollo';
  confidence?: number;
  firstName?: string;
  lastName?: string;
  position?: string;
  verified?: boolean;
}

Best Practices

• Rate limiting: Delay between requests (1s recommended)
• Respect robots.txt: Check before scraping
• Deduplicate: Normalize emails (lowercase, trim)
• Verify: Use MX record checks or API verification
• Filter: Remove noreply@, donotreply@ addresses

Legal & Ethical

• Comply with GDPR/CCPA
• Respect terms of service
• Honor opt-out requests
• Don't spam discovered emails

Integration

Works well with:

• leads-researcher - Discover contact emails after researching companies
• copywriter - Use found emails for outreach campaigns

For complete implementation code, API examples, verification patterns, and rate limiting utilities, see: references/full-guide.md