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SecurityTrailsDomainTools Whois Lookup
Freemium

An API key is available on sign-up; larger data services are aimed at security teams.

 Freemium

Basic lookups are free, with deeper history and reverse WHOIS research on paid plans.

Web Web
  • Historical DNS and WHOIS records going back years
  • Subdomain and associated domain discovery
  • Domain ownership and IP address history in one lookup
  • Shows whether a domain is available or for sale
  • Requires an account to use
  • Oriented towards business security teams rather than casual users
  • Free tier is limited
  • Historical and reverse lookups are aimed at paying users
Web application, Hosted service Web application
Closed source Closed source
License not stated License not stated
Account needed Not stated if an account is needed
Needs internet Needs internet

Checked October 1, 2026

Checked September 23, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.