The national top-level domain .io is assigned to the British Indian Ocean Territory. However, it is mainly used in IT circles and by Tech start-ups.
What is a .io domain?
The domain .io is a ccTLD, i.e. a country-specific top-level domain. However, most users do not know directly which country corresponds to .io ! This domain extension is assigned to British Indian Ocean Territory and was introduced in 1997. The domain is managed by the domain registrar Internet Computer Bureau (ICB), based in the United Kingdom, has been since 2017 a subsidiary of the American group Afilias, which notably administers TLDs .info, .mobi And .pro.
From the beginning, the domain .io did not have the significance of a country-specific extension; this is not surprising given that there are no legal, permanent residents of British territory in the Indian Ocean. Any natural or legal person, regardless of their place of residence or establishment, can register an address .io using 2 to 63 alphanumeric characters. Only addresses with second-level domains like .com, .net Or .gov are blocked. Registering a domain such as monbusiness.net.io is therefore not possible.
Advice
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What is the meaning of .io?
Initially, the domain .io has the meaning Indian Ocean (or Indian Ocean in French). However, no one associates this top-level domain with the British Overseas Territory, the last remnant of which is the Chagos Archipelago (a group of islands measuring 63.17 km2).
So what was the meaning assigned to the domain .io in recent years? There are two possible answers to this question:
- Input/Output (I/O or IO) : in computing, the abbreviation I/O means input/output, that is to say the communication of information systems like computers with the outside world. Thus, like the generic TLD .app which is the perfect extension for mobile app developers, the domain .io is of particular interest to Tech companies because of this significance.
- Domain hack : THE top level domain .io is also important for domain hack. With a little creativity, it can be combined with a matching domain name to create concise web addresses like
rad.ioOrportfol.io. A well-known example is the domainrub.ioused by American politician Marco Rubio for his presidential campaign in 2016.
Note
The company Levi Strauss & Co. registered levi.iothe first domain name to have the ccTLD .ioin 1998.
Why is .io so popular among IT and Tech companies?
According to the figures of w3techs.com, about 0.3% of all websites are registered under the TLD .io (in April 2025).
The use of this domain is mainly due to the possible meaning of its letter combination. .io indicates to potential visitors, such as developers or IT administrators, the focus of a website's content. Additionally, it also represents an easy-to-read and easy-to-pronounce alternative to popular domain extensions. .io therefore constitutes a good option if a domain name is no longer available under .comFor example.
Advantages and disadvantages of a .io domain
The TLD .iooriginally country specific, is now widely used in the Tech environment, but also for create fun and playful internet addresses. Here are the main advantages and disadvantages of a domain .io :
| Benefits | Disadvantages |
|---|---|
| ✓ Widely recognized | ✗ Not very accessible to people without computer experience |
| ✓ Many domain names are (still) available | ✗ Can be considered a signal of a weak brand |
| ✓ Perfect for domain hacking | ✗ Relatively expensive |
| ✓ Google deals .io like a generic TLD | ✗ Unlike other ccTLDs, revenue does not go to the owning country |
| ✓ Shorter than alternatives like .com Or .app |
Advice
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