Supriya Ghosh (Editor)


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Introduced  1997
Status  Active
TLD type  Country code top-level domain
Registry  NIC.IO (run by Internet Computer Bureau)
Sponsor  IO Top Level Domain Registry (Cable and Wireless)
Intended use  Entities connected with  British Indian Ocean Territory

The Internet country code top-level domain (ccTLD) .io is assigned to the British Indian Ocean Territory.


The .io domain is administered by the Internet Computer Bureau, a domain name registry company based in the United Kingdom.

Google's ad targeting currently treats .io as a generic top-level domain (gTLD) because "users and webmasters frequently see [the domain] more generic than country-targeted".


The .io domain extension has existed since 1997.

The first .io domain was registered in 1998, when Levi Strauss & Co. registered the domain


Labels for .io domains may only contain alphanumeric characters and hyphens and must be between 3 and 63 characters long. Domain names cannot begin with, or end with, a hyphen symbol, and may not contain two consecutive hyphens.The entire domain name may not contain more than 253 characters.


The right to administer domain names is given to approved organisations by the Internet Assigned Numbers Authority (IANA). The Internet Computer Bureau (ICB) administers .io domains. This domain name registry is a British company, and operates for this purpose under the name NIC.IO. The company also holds the rights to sell .sh-domain and .ac-domains, the top-level domains for the South Atlantic islands of Saint Helena and Ascension, respectively.

Registration and restrictions

Both individuals and organisations are allowed to register .io-domains.

In order to register .io domains you do not need to be registered or established in the British Indian Ocean territory. In order to register third-level domains such as you have to be an inhabitant of the area. Any second-level domains used by NIC.IO and top-level domains can not be used as a third-level domain. For example, the domain "", "" and "" are all restricted.

Domain names in .io may not be used "for any purpose that is sexual or pornographic or that is against the statutory laws of any Nation". Breaching this requirement "NIC.IO reserves the right to immediately deactivate the offending registration".

Dot-io domains may be registered for a minimum of one year, and a maximum of 5 years.

Domain names in .io are currently priced higher than those in other TLDs. Registering available .io-domains starts from around £30 / $32.88 US per year.


The .io-domain has considerable usage unrelated to the British Indian Ocean Territory.

"Nowadays, a lot of TLDs are used without any relation to the original country, such as .ly, .io, .me."

IO is also commonly used in IT as an abbreviation for input/output, which makes the .io domain useful for domain hacks and services wanting to be associated with technology.

"We took it because it refers to ‘input-output’. And our customers (mostly tech savvy people) understand it like so."

The .io gTLD has become a popular alternative for startup companies.

.io domains are often used for open source projects, APIs (such as API and API) and online services. is a shortened URL that was used for the 2016 U.S. presidential campaign of Marco Rubio. Likewise, is a shortened URL used for Hillary Clinton's 2016 U.S. presidential campaign.

Some popular browser-based games such as,,, and, called Io games, use the .io ccTLD. is a video game distribution service.


According to a Gigaom interview with Paul Kane, chairman of the Internet Computer Bureau, the domain name registry is required to give some of its profits to the British government, for administration of the British Indian Ocean Territory. As no indigenous Chagossians remain in the territory, the only residents being about 4,000 United States military personnel and contractors, it is contended that the indigenous Chagossians do not receive any monetary benefit from the sale of the domain names.

After being questioned as a result of the interview, the British Government denied receiving any funds from the sale of .io domain names, and argued that consequently, the profits could not be shared with the Chagossians.


.io Wikipedia