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NIC.IO -- .IO Domain Registry
Introduced 1997
TLD type Country code top-level domain
Status Active
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
Actual use Popular with startup companies; little of anything related to the territory itself.
Registration restrictions None for 2nd level registrations; 3rd level registrant must be resident of British Indian Ocean Territory
Structure Registrations are taken directly at the second level or at third level beneath various 2nd-level labels
Documents Terms & Conditions; Rules
Dispute policies Dispute Resolution Policy
Website NIC.IO

.io is the Internet country code top-level domain (ccTLD) for the British Indian Ocean Territory.[1]

The .io domain name is administered by the Internet Computer Bureau, a company based in the United Kingdom.[2]

Other than the Diego Garcia atoll, the territory has been uninhabited since the existing population was expelled in 1973 and has no government of its own. Google currently treats .io as a generic top-level domain (gTLD) because "users and webmasters frequently see [the domain] more generic than country-targeted".[3]


The .io domain extension has existed since 1997, and has grown steadily in popularity ever since. .io domains now compose 0.1% of all websites.[4]

The first IO-related domain to be registered was the domain data-io.com, which when it was registered in late 1986 was the 45th domain name ever to be registered.[5]

The first .io-domain was not registered until 1998, when Yahoo Inc registered the domain yahoo.io.[6]


Labels for .io domains may only contain alphanumeric characters and hyphens and must be between 3 and 63 characters long. Domain names can not begin with, or end with, a hyphen symbol, and may not contain two consecutive hyphens.[7][8] The entire domain name may not contain more than 253 characters.[9]


The right to administer domain names is given to approved organisations by the IANA. The Internet Computer Bureau administers .io domains. The Internet Computer Bureau is a British company that, in addition to the right to sell .io-domains, also holds the right to sell .sh-domains and .ac-domains, the top-level domains for Saint Helena and the South Atlantic islands of Ascension.[10]

Registration and Restrictions[edit]

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

In order to register .io domains you need not be registered or established in the British Indian Ocean territory. In order to register third-level domains such as xyz.com.io 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 "com.com.io", "org.com.io" and "biz.com.io" are all restricted.[11]

.io domains 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".[11]

.io domains may be registered for a minimum of one year, and a maximum of 10 years.[12]

.io-domains are currently priced higher than many other domains, partly due to high demand. Registering available .io-domains starts from around £30 / $32.88 US per year.[11][13][14]


To many[weasel words] the .io-domain is used with little thought of its origin.

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

—Jens Segers - Founder of Auki.io, [1]

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.[15]

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

—Ben Verbeken - Seats.io CEO, [2]


.io domains have become a popular alternative for startup companies.[16][17]

Online Services[edit]

IO also stands as an abbreviation for Internet Organization[citation needed]. In addition, .io domains are often used for open source projects, APIs (such as put.io API and pen.io API) and online services.[18]


One of the main reasons behind this popularity is the availability of .io domains: Though it is often hard to find a fitting .com domain, there are plenty of corresponding .io domains available that have not yet been registered. This may be due in part to registrations being suppressed by the relatively high price of .io domain names.


The .io registry operates a technical service of a secure and stable Top Level Domain. The popularity of the .io TLD has attracted attention, both good and bad.

There are activist parties who seek to draw the .io TLD into the controversy surrounding the depopulation of Diego Garcia in the 1970s, asserting that funds paid to the British Government from the registration of .io domains should be a means for the British Government to make reparations to displaced Chagossians. Two rather negative opinion articles, one a blog post with a sensational title, "The dark side of .io: How the U.K. is making web domain profits from a shady Cold War land deal" have been written on the GigaOM Blog[19] and The Independent[20] which quote carefully chosen segments of a quote from the registry operator in an attempt to establish a financial arrangement exists that could be a basis for reparations. These articles were based upon the false premise that the British Government has a financial arrangement with the domain name registrar for .io, and identify that finances received by the British Government should be put toward reparations to the Chagossians.

The British Government has since clarified the matter, which is published in the "House of Lords Summer Recess 2014 Written Answers and Statements", August 2014 which contains the following question and response regarding the sale of dependent territory domain names. The following is the excerpt of the respective clarification (HL1060):[21]

Question Asked by Lord Avebury:

To ask Her Majesty’s Government what if any financial arrangements they have with the Internet Computer Bureau which allow the latter to make money from the sale of dependent territory domain names.(HL1060)

Answer by Lord Popat (Con):

The British Government has no financial arrangement with the Internet Computer Bureau, which is the Domain Name Registrar or Network Information Centre for a number of domains including for some of the Overseas Territories.

The controversial articles contained inflammatory titles, inaccuracies, and carefully chosen quotations. These have been disruptive, and created negative publicity and consumer sentiment for the .io registry. The GigaOM blog later released a follow-up blog post[22] which clarifies that the .io registry is operated by Internet Computer Bureau, akin to how Nominet operate .uk, correcting the facts about the British Government's explanation following the clarification from the House of Lords.


  1. ^ IDN Code Points Policy for the .IO Top Level Domain (PDF), NIC.IO 
  2. ^ "IANA -.io Domain Delegation Data", Internet Assigned Numbers Authority, 28 March 2014
  3. ^ "Geotargetable domains". Google. Retrieved 6 May 2013. 
  4. ^ "Historical trends in the usage of top level domains for websites". Retrieved 2014-10-16. 
  5. ^ "The Oldest .io domains". Retrieved 2014-10-29. 
  6. ^ "NIC.IO - The Indian Ocean .IO Domain Registry and Network Information Centre - Whois Search". Retrieved 2014-12-29. 
  7. ^ ".IO Domain". Retrieved 2014-10-29. 
  8. ^ "Eigenschaften einer .io-Domain" (in German). United-Domains. 
  9. ^ RFC 1035, Domain names--Implementation and specification, P. Mockapetris (Nov 1987)
  10. ^ "Internet Computer Bureau". 
  11. ^ a b c "RULES for the .IO Domain and Sub-Domains". 
  12. ^ "Register dot IO (British Indian Ocean Territory) domain names". 
  13. ^ ".IO Domain at Gandi Rates". 
  14. ^ "NameCheap.com .IO domains". 
  15. ^ "WHY .IO?". 
  16. ^ "Popularity with startups". 
  17. ^ "The 676 Most Popular Domains .io.". Retrieved 4 May 2015. 
  18. ^ Beattie, Russell (2013-02-12). "The rise of .io domains for well crafted web services". Retrieved 2014-04-24. There's lots of open source projects (Redis, Brackets, Launcher), a few mobile-app landing pages (Avocado, X-Ray), a ton of new web apps and services, several conference pages (Lightning, Renaissance, Resonate) and a few older companies or organizations who've changed their name to take advantage of a cleaner .io name. 
  19. ^ "The dark side of .io: How the U.K. is making web domain profits from a shady Cold War land deal", David Meyer, 30 June 2014
  20. ^ Milmo, Cahal. "Government accused of profiting from sales of Chagos Islands '.io' domain name". Retrieved 4 September 2014. 
  21. ^ The UK Parliament House of Lords Summer Recess 2014 Written Answers and Statements (August 11, 2014) <http://www.publications.parliament.uk/pa/ld/ldtoday/writtens/11082014.htm> see 1060
  22. ^ "UK Government Denies Receiving IO Domain Profits"

External links[edit]