Compare software

DomainTools Whois LookupSecurityTrails
Freemium

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

 Freemium

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

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

Checked September 23, 2026

Checked October 1, 2026

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