RDAP: the modern replacement for WHOIS

WHOIS traditionally uses TCP port 43 and does not define one universal response format. RDAP is an HTTP API with JSON representations, status codes, links and service discovery. For generic top-level domains, ICANN moved to RDAP as the definitive registration-data service on 28 January 2025; country-code domains can follow different policies.

How RDAP differs from WHOIS

A structured response does not make every field public. Data can be redacted or exposed only to authorised requesters. A missing registrant name therefore does not mean a domain has no registrant.

How to read an RDAP response

RDAP also covers Internet number resources. Regional Internet registries expose information about IP networks and autonomous systems. Such a record identifies a resource holder or network operator; it does not necessarily identify the individual who used an address at a particular time.

Start with the WHOIS and RDAP overview, then compare network context with the 2ip IP information service. Registration records should not be treated as proof of an exact physical location. For an additional check, use 2ip WHOIS/RDAP lookup.

What to look for

Check the object type, status, registration events, nameservers and links to authoritative services. A domain expiry date does not promise immediate availability because lifecycle rules depend on the registry and registrar. The RDAP response format is specified in RFC 9083.