What Is an .io Domain? Meaning, Risks and How to Register (2026)

You've probably noticed web addresses ending in .io, especially on software companies, developer tools and browser games. If you're starting a business or naming a new product, you might be wondering whether a .io domain is a smart choice or a risky one. I've pulled the facts below from the .io registry's own site, ICANN's published statement and the Wikipedia entries on each domain ending, so you can decide with your eyes open.

What .io stands for

A .io domain is a country-code top-level domain, the same family as .uk, .de or .fr. According to Wikipedia, .io is assigned to the British Indian Ocean Territory and was introduced in 1997. The registry's own website calls itself the official .io domain registry and network information centre, and its footer credits Internet Computer Bureau Ltd, with registrar services powered by Name.com.

Although the ending belongs to a territory, you don't need any connection to it. The registry's site says anyone, anywhere can register, and that you're not required to live in the British Indian Ocean Territory. Names are issued on a first come, first served basis.

Why tech startups and games use a .io domain

• It reads as a tech term: Wikipedia notes that IO is the common abbreviation for input/output in computing, which gives the ending an instant technical feel.
• It's short: two letters after the dot keeps an address quick to type and easy to fit on a logo.
• Names are easier to find: Wikipedia points out that .io is less crowded than the biggest endings, so the name you want is more likely to be free.
• Gaming culture: Wikipedia says the ending became popular for browser games after Agar.io in 2015 and Slither.io in 2016, which kicked off what people now call .io games.

For a software product or a developer tool, that technical feel can be an advantage. For a local bakery, a salon or an accountancy practice, it may simply confuse customers who expect .co.uk or .com.

The .io sovereignty question in plain English

This is the part you'll want to read slowly. Wikipedia records that in 2024 the UK announced it would hand sovereignty of the Chagos Archipelago, which makes up the territory, to Mauritius once a treaty is finalised, and that an agreement was signed in 2025, to take effect once it enters into force.

Why does that matter for a domain? Country-code endings are tied to an international list of country codes. In a blog post published in 2024, ICANN explained that it relies on the ISO 3166-1 standard to decide which countries and territories get a two-letter code. The same post said that IO remained in that standard and that there had been no change to it as a result of the announcement.

ICANN also set out what would happen if IO were ever removed from the standard: its retirement policy would apply, giving a five-year window to phase out use of the domain, and that window might be extended in some circumstances. The post described much of the online discussion as speculation and said a change in sovereignty doesn't automatically mean a change to .io. Wikipedia adds that exceptions have been made before, citing .su, the old Soviet Union ending.

So the honest summary is this: nothing has been decided about .io itself, there's a long published process if anything does change, and you should check the latest position from ICANN and the registry before you build a brand on it.

What to check before you choose a .io domain

• Who your customers are: tech buyers recognise .io straight away. Everyday consumers may not, and some will type .com by habit.
• Renewal terms: Wikipedia says registrations run from one to five years. Read your registrar's renewal terms in full, not just the first-year offer.
• The registry's rules: Wikipedia notes that names can use letters, digits and hyphens, can't start or end with a hyphen, and that the registry may deactivate names used for content it doesn't allow. Read the allocation rules on the registry site.
• The sovereignty position: look for any recent update from ICANN or the registry before you commit.
• Your plan B: decide which other ending you'd move to if you ever had to, and register it now.

If you're still weighing up the name itself, my guide on choosing the perfect domain name for your brand walks through the bigger branding decisions.

How to register a .io domain, step by step

1. Check the name you want is free, using the search box on the registry site or any registrar that sells .io.
2. Choose a registrar. The registry's site credits Name.com for registrar services, and many other registrars also sell the ending; check that yours lists .io before you start.
3. Search for the name, add it to your basket and choose how many years to register it for.
4. Enter your details accurately. Use your business's name and an email address you'll always control.
5. Switch on auto-renew and two-step login on your registrar account.
6. Point the domain at your website and email using the DNS settings your registrar provides.
7. Register your .com and your country ending as well, if they're available, so customers who guess the wrong ending still reach you.

Ending	Description, per Wikipedia	Often chosen by
.io	Country code for the British Indian Ocean Territory	Software startups, developer tools, browser games
.ai	Country code for Anguilla	AI companies and projects
.co	Country code for Colombia, used internationally	Startups wanting a short alternative
.app	Generic ending run by Google Registry, HTTPS required	Apps and web apps
.com	The original generic commercial ending	Almost every kind of business

Alternatives to a .io domain

Wikipedia describes .ai as the country code for Anguilla, popular with AI companies because it spells out AI. It describes .co as the country code for Colombia, popular in Colombia and internationally. The .app ending is a generic domain run by Google Registry, and Wikipedia notes it's on the HSTS preload list, so every .app site has to use a secure HTTPS connection. The .dev ending is another option many developers look at.

For most small businesses, a .com or a country ending such as .co.uk is still the safest choice, because it's what customers expect. A .io can sit alongside it as a product or campaign address. My article on using your domain name as a marketing tool has more ideas on getting value from the address you pick.

Protecting your brand when you use a .io domain

• Register the matching .com if you can, and point it at your .io site.
• Keep both domains on auto-renew in the same account, in your business's name.
• Use an email address on your main domain, so your inbox doesn't depend on a single ending.
• Write down where your DNS is managed, so moving later is a quick job.
• If your brand name matters legally, check with a solicitor or your trade mark office about protecting it; that's a separate step from registering a domain.

Myths about .io domains

• You have to live in the territory: not true. The registry says anyone, anywhere can register.
• .io will vanish overnight: ICANN's own post describes a five-year phase-out window if the code were ever removed, and says much of the talk is speculation.
• A .io domain ranks better in search: nothing in the official sources says the ending itself gives you an advantage. Good content and a clear site matter far more.
• Only tech companies can use .io: any business can register one; the question is whether your customers will remember it.

If you're setting up your first site to go with your new domain, my roundup of free website builders for small businesses shows which builders let you connect a domain you already own.

Frequently asked questions

What does .io mean in a web address?

It's the country-code ending assigned to the British Indian Ocean Territory. Tech companies like it because IO is also shorthand for input/output in computing.

Can anyone register a .io domain?

Yes. The registry's own site says anyone, anywhere can register a .io name, and you don't need to live in the territory.

Is the .io domain going away?

Nothing has been decided. ICANN said IO remains in the international code list and that, if it were ever removed, a five-year phase-out window would apply and could be extended. Check ICANN and the registry for the latest position.

Is a .io domain good for a small business?

It can suit software, tech and gaming brands. For local or everyday businesses, a .com or country ending is usually easier for customers to remember, and you can still own a .io alongside it.

How long can I register a .io domain for?

Wikipedia says registrations run from one to five years. Your registrar will show the options at checkout, and auto-renew helps you avoid losing the name.