What is .cz?
A little context on Czechia: the capital is Prague, languages include Czech and Slovak, the currency is the Czech koruna (CZK) and the international dialing code is +420. It's landlocked.
Czechia shares land borders with 4 countries, so the ccTLDs next door are .at (Austria), .de (Germany), .pl (Poland) and .sk (Slovakia).
IANA lists CZ.NIC, z.s.p.o as the manager of .cz, with an address in Czechia. The registry's website is http://www.nic.cz. ccTLD managers set their own policies — who can register, which second-level names exist, pricing to registrars — so those rules differ from country to country.
On the technical side, .cz is served by 4 authoritative name servers, every one of them reachable over IPv6. It is also DNSSEC-signed: the root zone carries a DS record for .cz, which lets validating resolvers check its answers cryptographically. Registration data is published over RDAP and WHOIS (the WHOIS server is whois.nic.cz).
.cz FAQ
What country is .cz?
.cz is the country-code top-level domain for Czech Republic (Czechia), in Central Europe.
What is Czech Republic's domain extension?
Czech Republic's website extension is .cz, its country-code top-level domain. "CZ" is its ISO 3166-1 alpha-2 code.
Who owns the .cz domain?
IANA lists CZ.NIC, z.s.p.o as the manager of .cz: it runs the registry and sets the rules for Czechia's ccTLD. Individual .cz names belong to whoever registers them.
Can I register a .cz domain from the US?
It depends on CZ.NIC, z.s.p.o's policy. Some ccTLDs are open to anyone in the world, while others require a local address, company or trademark. Check the registry (http://www.nic.cz) or an accredited registrar before you buy.
Is .cz DNSSEC-signed?
Yes. The root zone has a DS record for .cz, so DNSSEC validation works all the way down from the root.
How do I look up who owns a .cz domain?
Query the registry's registration data service: the WHOIS server is whois.nic.cz, and RDAP lookups go to https://rdap.nic.cz/. Many registrants use privacy services, so personal details may be hidden.
Sources
Data from IANA root zone version 2026102000. Last changed March 7, 2023. Spotted something wrong? Tell us.
