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Resources for RDAP Implementers

On 27 February 2019, the ICANN org issued a notification to gTLD registries and registrars of the requirement to implement an RDAP service by 26 August 2019, including a recommendation that implementation occur according to the February-2019 gTLD RDAP Profile.

RDAP enables users to access current registration data and was created as an eventual replacement for the WHOIS protocol. RDAP was developed by the technical community in the Internet Engineering Task Force (IETF). RDAP runs on top of HTTP(S); the protocol on which the web runs.

The RDAP standard is described in IETF RFCs 7480 - 7484, and 8056, available here.

The RDAP RFCs are similar to a menu of functionalities. They describe how certain sets of functionalities work, but do not define which should be included in a given implementation. The RFCs leave those defining decisions to implementers or to those that set requirements on implementers. In the gTLD space, there are contractual and policy requirements that registries and registrars have to abide by. One or more documents are needed in order to map those contractual and policy requirements, as well as define which functionalities from the RDAP RFCs should be included. These documents collectively are called the gTLD RDAP profile.

The ICANN organization knows of the following RDAP server open-source projects that may be available for registries and registrars to use, should they decide not to code their own implementation:

The ICANN organization also knows of the following RDAP server conformance verification tools that may be available for registries and registrars to verify their implementations:

(*Please note that inclusion of the above links does not imply ICANN's endorsement nor any guarantee of compliance with applicable requirements. Implementers should do their own research and contact the external sites for answers to questions regarding their content.)

ICANN's RDAP conformance tool

On February 2022, the ICANN organization published the RDAP conformance tool as a stand-alone, open source tool that can be used to verify if an RDAP server implementation is conformant with the RDAP standards developed by the IETF and optionally, the gTLD RDAP profile.

RDAP for gTLD Registries and Registrars Webinar 11 April 2019

Contact Global Support with questions related to RDAP.

Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."