Domain Restrictions

General Domain Rules

The rules below apply to domains registered through 365i. Every domain is also subject to the terms of its registry, and those terms change from time to time. Where a registry restricts who may hold an extension, we flag it on that extension’s page before you buy.

• Your domain must be available, meaning it is not already registered by somebody else. You can check with our domain search tool.
• Domain names are not case-sensitive. EXAMPLE.CO.UK and example.co.uk are the same domain.
• Short names are permitted. One and two-character domains are valid under most extensions, including .com and .uk. They are scarce rather than banned: almost all were taken years ago, and a few registries release them only by auction.

Character Restrictions

In its standard form, the part of the domain before the extension may contain only:

• Letters: a–z
• Numbers: 0–9
• Hyphens (-), but never as the first or last character

The following are not permitted:

• Special characters such as #, *, %, &, !, or @
• Spaces
• A hyphen at the start or end of the name
• Hyphens in the third and fourth positions together, as in “ab--cd”. That pattern is reserved to mark an internationalised domain name.

Many registries also accept internationalised domain names (IDNs), which allow accented and non-Latin characters. An IDN is stored and transmitted as an ASCII string beginning “xn--”, which is precisely why the third and fourth hyphen positions are held back. IDN support varies by extension, so check with us before you build a plan around one.

Length Limits

These limits come from the DNS standard itself (RFC 1035) and apply to every extension:

• Minimum: 1 character
• Maximum: 63 characters for the name, not counting the dot or the extension
• Full address: 253 characters in total, including the extension and any subdomains

You will sometimes see 67 quoted as the limit for a .com. That figure includes the four characters of “.com” itself. The name you type before the dot is still capped at 63, and the same 63-character ceiling applies to .net, .org, .info, .co.uk and the rest.

Registries may apply tighter limits of their own, or hold back short names, so treat 63 as the technical ceiling rather than a promise for every extension.

Common Generic Extensions

Below are common generic top-level domains available through 365i and their typical usage. None of these carry an eligibility check at the point of registration unless stated.

.com

Commercial or personal websites. The most widely recognised extension in the world.

.net

Originally for network and infrastructure providers, now used generally.

.org

Associated with not-for-profits, communities and open-source projects, but open to anyone.

.info

Information-based sites, commercial or personal. No restrictions.

.biz

Intended for business and commercial use. The registry’s terms require a bona fide business purpose, though registrations are not vetted before they go live.

.mobi

Originally for mobile-optimised sites. No longer meaningfully restricted.

Country-Specific Extensions

Country-code top-level domains (ccTLDs) are governed by their national registry, and several require a local connection. The requirements below are the ones most likely to catch out a UK buyer.

.co.uk

United Kingdom. Open to individuals and businesses, in the UK or overseas. No eligibility restrictions.

.org.uk

United Kingdom. Long associated with charities, community groups and non-profits, but Nominet applies no eligibility restrictions: anyone may register one.

.uk

United Kingdom. Open to anyone, on the same terms as .co.uk.

.eu

European Union. Open to EU citizens wherever they live, and to residents and organisations established in the EU, Iceland, Liechtenstein or Norway. Since the Brexit transition period ended on 31 December 2020, a UK resident who is not an EU citizen is not eligible to hold one.

.us

United States. Requires a US nexus: you must be a US citizen or permanent resident, an organisation formed under US law, or have a bona fide US presence such as an office or regular trading there. Registrants self-certify, and a false certification can cost you the domain.

.ca

Canada. Requires a Canadian presence under CIRA (Canadian Internet Registration Authority) rules.

.de

Germany. Open to registrants worldwide, but DENIC requires an administrative contact with a postal address in Germany so that legal notices can be served locally.

.jp

Japan. Requires a postal address in Japan for the registrant. A UK-only business cannot register one directly.

.cc

Cocos (Keeling) Islands. Unrestricted in practice and widely used as a general-purpose extension.