A ccTLD, or country-code top-level domain, is a two-letter ending such as .uk, .in, .au, .my, .jp or .np that is associated with a country or territory. Every ccTLD is run by an organization designated for that country, under rules it sets itself or that are set nationally. That local control is what makes ccTLDs interesting: two domains that look similar can have very different eligibility rules, structures and data policies.
Where the two-letter codes come from
The ASCII ccTLDs are based on the two-letter country codes in the ISO 3166-1 standard. IANA, the body that manages the DNS root zone, does not decide what is or is not a country. It follows the ISO list, which is why territories as well as sovereign states have ccTLDs. There are a small number of historical exceptions, the best known being .uk, which is used for the United Kingdom even though the ISO code is GB.
ccTLDs versus gTLDs
Top-level domains fall broadly into two groups:
- Generic TLDs (gTLDs) such as .com, .org, .net and the many newer ones. Their registries operate under contracts with ICANN, which sets common rules on things like registration data, transfers and dispute resolution.
- Country-code TLDs (ccTLDs), which are delegated to a manager for a particular country or territory. Most ccTLD managers do not have gTLD-style registry contracts with ICANN, so they decide their own policies.
In practice, that means ccTLDs can differ on almost everything:
- who is eligible to register;
- whether names are registered directly under the TLD, at the second level such as example.co.uk, or both;
- which documents are required, if any;
- whether registration goes through commercial registrars or directly with the registry;
- what registration data is published, and whether it is available via RDAP, WHOIS or neither;
- how expiry, grace periods and deletion work;
- how disputes are resolved.
Some ccTLDs are run in a way that is open to anyone worldwide, and a handful are marketed internationally because their two letters happen to spell something useful. Others are restricted to citizens, residents or locally registered organizations.
Second-level structures
Many ccTLDs historically organized registrations under category zones at the second level, similar to how .com and .org divide names by purpose. Some have since added direct registrations under the TLD itself, keeping the older zones alongside them.
A few examples, described in general terms (always check the registry for current rules):
- United Kingdom: the long-established example.co.uk for commercial use and example.org.uk for organizations, alongside direct registrations such as example.uk.
- India: direct names such as example.in, plus zones including example.co.in and example.org.in. Some zones, such as those for government and education, are restricted.
- Australia: example.com.au and example.org.au, which have historically required an Australian connection, plus direct example.au registrations introduced more recently, also with an Australian presence requirement.
- Malaysia: zones such as example.com.my alongside direct example.my registrations.
- Japan: example.co.jp for companies registered in Japan, and general-use example.jp names, which require a local address in Japan.
- Nepal: registrations are made at the third level only, under zones such as example.com.np and example.org.np, with document-based review. See Understanding .np domains.
Because of structures like these, software cannot assume that the registrable part of a name is "the last two labels." The Public Suffix List, a community-maintained list used by browsers and many tools, records which names act as suffixes. It is what lets a browser know that example.co.uk and other.co.uk are separate sites, even though they share "co.uk."
Local presence rules
Eligibility requirements are among the biggest practical differences between ccTLDs. Typical patterns include:
- Open: anyone, anywhere, can register.
- Local presence: the registrant must be a citizen, resident or locally registered organization, or must have a demonstrable connection to the country.
- Trustee or agent arrangements: some registries allow a local agent to meet the presence requirement, while others prohibit this.
- Category restrictions: particular zones are reserved for specific kinds of entity, such as government bodies, universities or registered companies.
These rules change over time and differ between zones of the same ccTLD. Treat any summary, including this one, as a starting point and confirm with the registry or an accredited registrar before relying on it.
IDN ccTLDs
Not every ccTLD uses Latin letters. Internationalized domain name (IDN) ccTLDs let countries use their own script at the top level. Examples include .рф for Russia, .中国 for China and .भारत for India.
In the DNS itself, these labels are stored in an ASCII-compatible form called Punycode, which always begins with xn--. The Unicode form is what users see in the browser; the Punycode form is what resolvers and zone files use. An IDN ccTLD is usually run alongside the country's ASCII ccTLD, sometimes by the same operator and sometimes by a different one, and it can have its own registration rules.
Registration data and lookups
Because ccTLDs set their own data policies, lookups behave differently across them:
- Many ccTLDs provide RDAP and are listed in IANA's bootstrap file, so standard RDAP clients can query them.
- Some offer only WHOIS or a web search form.
- Some publish little or no registration data, especially about individuals.
If an RDAP lookup reports no service for a ccTLD, you can still learn a good deal from DNS. A domain that has NS records delegated from its parent zone is definitely registered. The reverse is not true: a name with no delegation may still be registered, reserved or blocked, so the absence of DNS records does not prove a name is available.
example.co.uk. NS ns1.example.net.
example.co.uk. NS ns2.example.org.
Check it yourself
- RDAP Lookup tells you whether a ccTLD offers RDAP and, if it does, shows the registration details it publishes.
- DNS Lookup shows whether a name is delegated and which nameservers it uses, which works for any TLD regardless of its data policy.