.io
 |
|
| 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 |
| DNSSEC | yes |
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 levi.io.
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.
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 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.
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