RDAP vs WHOIS: Where Domain Ownership Lookups Went
· Reference · RDAP
Quick answer
What replaced WHOIS, and where can you look up a domain owner?
The Registration Data Access Protocol (RDAP) replaced the older WHOIS protocol for generic TLD registration data. It returns structured JSON over HTTPS instead of free-form port-43 text, and ICANN’s Lookup service is a public entry point. Many registrant details are still redacted because of privacy law and registrar policy, so a lookup often confirms dates, status and registrar rather than a person’s name.
What changed
WHOIS answered queries on port 43 with an unstructured text blob whose format varied between servers. RDAP is a web protocol: a client makes an HTTPS request and receives standardised JSON, with defined fields for status codes, events and entities. RFC 7480 describes how RDAP is carried over HTTP.
ICANN completed the transition away from requiring WHOIS for gTLD registration data in early 2025, making RDAP the definitive protocol for that data. Country-code TLDs are not governed by ICANN in the same way and their lookup services vary.
Why the answer is often redacted
Public registration data is constrained by privacy law and by ICANN policy, so personal contact details are commonly withheld or replaced with a relay. A normal lookup still tells you useful, verifiable things: the registrar, creation and expiry dates, name servers and EPP status codes such as clientTransferProhibited.
Reading a lookup like a buyer
For a domain you are considering on the aftermarket, the creation date and registrar history matter more than a hidden registrant name. Status codes tell you whether a name is locked against transfer, which is directly relevant to the transfer article in this series. For the authoritative delegation question — whether the TLD itself exists — use the IANA root zone database instead.
Frequently asked questions
Is WHOIS completely gone?
RDAP is the definitive protocol for gTLD registration data under ICANN policy, but some registrars and ccTLD registries still expose WHOIS endpoints. Treat those as legacy interfaces.
Why can I not see the owner’s name and address?
Registrant personal data is commonly redacted to comply with privacy law and registrar policy. RDAP can also apply differentiated access for legitimate requestors, but an anonymous public query will usually see redacted fields.
Can RDAP tell me if a domain is available to register?
It can tell you that a registration currently exists and show its status. Availability and price are registrar and registry questions, not RDAP questions.
Sources
Primary sources for the claims above.