RDAP (Registration Data Access Protocol) is the modern way to look up domain registration records; WHOIS is the older protocol and service family. To check a domain, open ICANN Lookup, enter the domain name, and review the record. For generic top-level domains (gTLDs), RDAP became the definitive source for registration information on 28 January 2025. A public lookup may omit or redact personal details, so it cannot be relied on to reveal a registrant’s identity.
What are RDAP and WHOIS?
RDAP stands for Registration Data Access Protocol. WHOIS is pronounced “who is”; it is not an acronym. The IETF technical community developed RDAP as a replacement for WHOIS. Both relate to access to domain registration information, but RDAP uses standardized query and response formats and can help a client discover the authoritative service for a registration.
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RDAP is a protocol, not a particular website. A browser lookup tool or command-line client sends a query to an RDAP service and presents the returned data. ICANN describes RDAP as supporting standardized responses, internationalization, secure access, differentiated access, and authoritative server discovery. These features make data access more consistent; they do not guarantee that every record will publish the same fields.
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- Open ICANN Lookup. ICANN describes the browser-based RDAP client as free to use.
- Enter the domain name and submit the query.
- Review the registration record. Depending on what is published for that domain, it may show registration and expiration events, registrar details, status information, and nameservers. Not every record includes every field.
- For repeat or scripted checks, consider ICANN’s open-source RDAP command-line client rather than submitting each lookup manually.
ICANN estimated in December 2024 that RDAP servers handled more than 10 billion queries per month across all types of RDAP servers. That is a dated estimate, not a current 2026 count.
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How is RDAP different from WHOIS?
Traditional WHOIS queries ask a particular registry or registrar database for information. RDAP adds standardized response formatting and bootstrap discovery, which helps a client route a query toward the authoritative server for the requested registration. It also supports internationalized data and secure, differentiated access.
The transition is specific to gTLD registration information, not every domain extension worldwide. ICANN announced that RDAP became the definitive source for gTLD registration information on 28 January 2025. From that date, gTLD registries and registrars were no longer required to provide WHOIS, with exceptions for .com, .name, and .post. The guidance does not establish the current RDAP or WHOIS arrangements for every country-code top-level domain (ccTLD); check the relevant registry for a particular extension.
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What can a lookup record tell you—and what can’t it prove?
A lookup returns registration information supplied through registry and registrar data services. It is not proof that a website is safe, that the registrant’s identity has been independently verified, or that the domain is available to register. ICANN says it is not responsible for profile content or verification of user details.
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What if the information you need is not public?
Start with ICANN Lookup. If nonpublic gTLD registration information is not available there, ICANN points requesters to the Registration Data Request Service (RDRS) for participating registrars, or to the sponsoring registrar’s own disclosure process. RDRS is voluntary; follow the relevant registrar’s current process, and do not assume a request will be granted.
ICANN’s Registration Data Policy FAQ, dated 21 August 2025, says the policy took effect that day. It explains that contracted parties handle and redact registration data in accordance with the policy and applicable legal requirements. For a specific disclosure request, use the registrar’s current instructions rather than treating a general guide as legal or operational advice.
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