Subdomain Finder
Discover subdomains using certificate transparency and OSINT sources.
Enter a root domain without www (e.g., example.com, not www.example.com)
Enter a domain to discover its subdomains
About Subdomain Finder
This tool discovers subdomains by querying certificate transparency logs and other public sources. It's useful for security assessments and understanding your external attack surface.
How it works
We query multiple data sources including certificate transparency logs (crt.sh, Certspotter), which contain records of all SSL certificates issued for a domain, revealing subdomains that were issued certificates.
Use Cases
- Security assessments and penetration testing
- Asset inventory and shadow IT discovery
- Monitoring for unauthorized subdomains
- Competitive analysis and research
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