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WHOIS vs RDAP: what they are and how they differ

When someone registers a domain, the registry and registrar keep a record of it. WHOIS is the old way to read that record and RDAP is its replacement. Both answer the same questions: who is the registrar, when does it expire, which nameservers does it use.

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WHOIS

WHOIS dates from the early internet. A client connects to a server on port 43, sends a name and gets back plain text (RFC 3912). It worked, but it has well known limits:

  • The text has no fixed layout, so every registry words and orders it differently and programs struggle to parse it.
  • There is no standard way to find the right server for a name.
  • It's unencrypted and has no way to give different people different levels of detail.

RDAP

RDAP, the Registration Data Access Protocol, answers the same question with structured JSON over HTTPS (RFC 7480). The registrar, dates, status codes and nameservers sit in the same fields everywhere, and a public bootstrap file from IANA tells a client which server is authoritative for each top-level domain. A server can also show more to an authorised party than to the public, and names and addresses can use international text.

ICANN made RDAP the required lookup service for generic top-level domains such as .com, and the old WHOIS requirement was relaxed from early 2025. This site reads RDAP, so what you see on the WHOIS lookup comes from the registry itself. Some country domains don't publish RDAP, and for those no registration data can be shown.

What a record contains

FieldMeaning
RegistrarThe company the domain was registered through
CreatedThe date of first registration
ExpiresWhen the registration ends if it isn't renewed
StatusCodes such as clientTransferProhibited, which means the domain is locked against transfer
NameserversThe servers that answer DNS for the domain
DNSSECWhether the domain is signed

Why the owner is usually hidden

Before 2018 most records listed the registrant's name, address, email and phone. Since the GDPR, registrars redact those personal details for nearly all domains, and records usually show REDACTED in their place. This protects people and reduces spam, but it also means a lookup rarely tells you who really owns a domain. If you need to contact the owner, use the abuse or contact form the registrar provides.

Useful things to check

  • Expiry date. A domain that lapses can be registered by someone else. See how domain expiration works, and use the expiry checker to get the days left.
  • Transfer lock. A clientTransferProhibited status is a good sign. It stops an unauthorised move.
  • Nameservers. If they changed and you didn't change them, that may be a hijacking.
  • Age. Very new domains deserve extra care in phishing and spam checks.

Frequently asked questions

What is the difference between WHOIS and RDAP?

WHOIS is a plain-text protocol on port 43 with no fixed format. RDAP returns structured JSON over HTTPS, has a standard way to find the right server, and supports access control and internationalised text.

Why is the domain owner not shown in WHOIS or RDAP?

Since the GDPR took effect in 2018, registrars redact personal details for most domains. You typically see the registrar, dates, nameservers and status, with owner fields marked as redacted.

Is WHOIS going away?

RDAP is the replacement. ICANN made RDAP the required service for generic top-level domains, so many registries and registrars now answer RDAP first. Plenty of WHOIS servers still run.

How do I find when a domain expires?

Look at the expiration date in the registration record. The domain expiry checker on this site reads it from RDAP and shows the days left.