Whois is a service that provides basic information about a registered domain, such as domain owner contact information, domain availability status and the company with which the domain is registered (also called the Registrar). Whois also provides registration and expiration dates of a domain as well as the nameservers the domain is using. ICANN regulations require all domain registrants to keep their contact details valid and up-to-date to help prevent fraud and identity theft.

Domain registrars usually allow their customers to change their domain contact information directly from their accounts (without needing to contact the Registrar's customer support). Updates to Whois information may take up to 24 hours.