What is WHOIS?

The original plain-text protocol (port 43) for looking up who registered a domain.

A WHOIS query returns free-form text from the registry, and for thin registries like .com also from the registrar. Field names differ between registries, which is why parsing WHOIS reliably is hard.

Since GDPR (2018) most personal registrant details are redacted. Abuse contacts and registrar details remain public.

Try it

• WHOIS lookup tool
• WHOIS API

Related terms

• RDAP: The Registration Data Access Protocol, the JSON-over-HTTPS successor to WHOIS.
• DNS: The Domain Name System, which maps names like example.com to IP addresses and other records.
• A record: A DNS record that points a hostname to an IPv4 address.