Top-Level Domain

The top-level domain (TLD) is the right-most string, or series of characters, in every web address. The domain name system allows users to refer to websites and other Internet resources using names rather than the all-numeric IP addresses assigned to each computer on the Internet. Every TLD is managed by a single registry.

TLD Growth - Overview from 1983 to 2021

Dates TLDs Use Reason Significance
1983 .no country code TLD Restricted to use by entities in Norway The first two-letter country code based on the ISO 3166-1
October 1984 .com, .net, .org Open Any person or entity is permitted to register a domain name using these TLDs The first gTLDs
October 1984 .edu, .gov, .mil Limited; an entity has sponsored the operation of this TLD For higher educational institutions, United States governmental entities and agencies, and divisions, services and agencies of the United States Department of Defense, respectively The first gTLDs
1985 .us, .uk .il ccTLDs USA, UK, Israel GB is the UK's ISO 3166 country code. However, JANET NRS defined UK as the top-level domain a few months before the ISO-derived list; it was registered on July 24, 1985.
1986 .au, .de, .fi, .fr, .is, .kr, .nl, .se ccTLDs Australia, Denmark, Finland, France, Iceland, South Korea, Netherlands, Sweden The next eight ccTLDs
November 3, 1988 .int Limited; sponsored For organizations, offices, and programs endorsed by a treaty between two or more nations In response to a request by NATO
March 1994 Jon Postel's RFC 1591 establishes the baseline standards for eligible TLDs.
1996 Jon Postel drafts "New Registries and the Delegation of International Top Level Domains"
1998 Domain deregulation; ICANN is formed to oversee Internet names and numbers
May 2000 .arpa Limited; sponsored All Internet infrastructure databases one of the original TLDs, .arpa is re-designated at this time as an Address and Routing Parameter Area, critical to maintaining the stability of the Internet
November 16, 2000 .aero, .biz, .coop, .info, .museum, .name, .pro Sponsored gTLDs
June 29, 2006 Test domains per ICANN Board Resolution 07.47 eleven such domains have been delegated thus far
2007 .cat, .eu, .asia Sponsored specifically for a cultural, ethnic, or regional group Represents Catalan language and culture, the countries in the European Union, and the Asian continent, respectively The first TLDs to denote geographical, geopolitical, ethnic, social, or cultural representation
October 30, 2009 IDN ccTLD Fast Track Process is approved by the ICANN Board
.jobs, .mobi, .tel, .travel limited to entities having something to do with the phrase comprising the TLD in question
May 5, 2010 مصر السعودية امارات IDN ccTLDs From right to left, for Egypt, Saudi Arabia, and the United Arab Emirates For the first time in the history of the Internet, non-Latin characters are being used for top-level domains
April 2011 .xxx Sponsored gTLD ICM Registry had submitted proposals for this sTLD for pornographic sites since 2000
June 20, 2011 .post sTLD last TLD before New TLD Program ICANN Board votes to dramatically increase the number of gTLDs from the 22 already in operation
January 12, 2012 community or standard applicant decides if the nTLD is for a defined community consisting of a restricted population; the distinction between sponsored/unsponsored TLDs is deemed irrelevant to this round of nTLDs The application window for All New gTLD Applications opens
June 13, 2012 .scot community nTLD application for Scottish culture Reveal Day: 1,930 applications for new gTLDs submitted; 751 of which were contested
July 15, 2013 .сайт, .онлайн, .شبكة, .游戏 IDN nTLDs (xn--80aswg) – Russian for "site"; (xn--80asehdb) – Russian for "online"شبكة (xn--ngbc5azd) – Arabic for "web/network"; (xn--unup4y) – Chinese for "game(s)" First four nTLD aggreements signed
September 15, 2014 .prof -- -- 400th nTLD was delegated
20 May 2017 ccTLDs -- -- 255 ccTLDs delegated
June 2020 IDN ccTLDs -- -- 61 IDN ccTLDs approved
October 17, 2020 .spa nTLD latest delegated nTLD IANA lists 1589 TLDs (1503 in use, 67 not assigned/revoked, 8 retired, 11 test domains)

Varieties of TLDs

There are different types of TLDs.


  • the original generic top-level domains
  • sTLDs - has a sponsor for a specific purpose, such as to represent a specific ethnic community, professional group, or geographical location.
  • nTLDs - domains that were introduced beginning in October 2013
  • community TLDs relate to local events, gatherings, organizations, or communities, in essence replacing sTLDs
  • geoTLDs represent geographical or regional areas that are not countries with three or more ASCII characters.
  • brand TLDs - corporations use their corporate name as their website's top-level identifier instead of .com or .biz domain space
  • hSTLDs


Country-code TLDs are delegated to a designated ccTLD registry, which is operated by a ccTLD Manager, according to local policies that are adapted to meet the economic, cultural, linguistic, and legal circumstances of the country or territory involved.

TLDs with two ASCII characters have been established for over 250 countries and external territories, including Strings eligible under ICANN Board Resolution 00.74 (currently this category applies to only one domain, .eu) ICANN - Board Resolution on the Delegation of ccTLDs, and "Grandfathered" TLDs from prior to 2000, based on "exceptionally reserved" codes in the ISO 3166-1 standard (this category currently applies to two TLDs - .uk and .ac);
TLDs with non-ASCII characters designated for a country or geographic region.

Operating Mode

TLDs operate in different manners but can be categorized in some simple ways:

  • Open - Operating and offering both registration and resolution services.
  • Closed - Not accepting registrations, may be resolving evergreen/legacy/infrastructure subdomains.

Level of Restriction

  • Unrestricted - If there are no requirements that must be met in order to register a name under a TLD, that TLD is Unrestricted.
  • Restricted - Requiring Local Physical Address, Local Tax ID, or other specific criteria to qualify.

Reserved Names

Some domain names are reserved, which means they can only be used (if at all) by the entities for whom they are reserved.