.cz

Overview

• .cz is the country code top-level domain (ccTLD) for the Czech Republic.
• It is administered and sponsored by CZ.NIC (CZ.NIC, z.s.p.o).
• Intended for entities affiliated with the Czech Republic and widely used within the country.
• DNSSEC is supported.

History

• The .cz domain came into effect in January 1993 following the dissolution of Czechoslovakia (previously .cs was used).
• Implementation/delegation date recorded as 13 January 1993.
• Growth milestones:
  • Over 850,000 .cz domains registered by the end of 2011.
  • Exceeded one million registrations in 2012.
  • 1,502,253 registered domains reported by CZ.NIC as of 2025-08-08.
• At the end of 2011, registrant composition was reported as approximately 58% individuals and 42% organisations.
• Domains have been most popular in Prague, followed by Brno and Ostrava.

Usage and Audience

• Typical users: businesses, organisations and individuals affiliated with the Czech Republic.
• The TLD is very popular within the Czech Republic and commonly used for Czech-focused websites.

Registration Rules

• Registry: CZ.NIC (registrations must be placed through accredited registrars).
• Eligibility / restrictions:
  • Businesses are required to provide a tax registration number.
  • Names can be registered directly at the second level.
• Allowed characters and format:
  • Permitted characters: letters a–z, digits 0–9 and the hyphen (-).
  • Hyphen cannot be the first or last character and may not appear consecutively.
  • Maximum length for a domain name is 63 characters.
• Policy and governance:
  • CZ.NIC publishes registration rules and maintains dispute-handling procedures and related documentation.
• International characters:
  • CZ.NIC has historically chosen to offer only standard ASCII characters (no diacritics) citing accessibility and demand concerns.

SEO and Brand Impact

• The .cz extension is strongly associated with the Czech market and national identity, making it suitable for Czech-targeted branding and local presence.
• Its widespread domestic use and CZ.NIC management contribute to recognition and trust within the Czech Republic.

Notable Cases or Examples

• Historical note: prior to 1993, Czechoslovakia used the .cs domain; .cz replaced it after dissolution.
• Milestone: the .cz namespace surpassed one million active domains in 2012, marking significant domestic adoption.

% IANA WHOIS server
% for more information on IANA, visit http://www.iana.org
% This query returned 1 object

domain:       CZ

organisation: CZ.NIC, z.s.p.o
address:      Milesovska 5
address:      Prague 130 00
address:      Czechia

contact:      administrative
name:         Ondrej Filip
organisation: CZ.NIC, z.s.p.o.
address:      Milesovska 5
address:      Prague 130 00
address:      Czechia
phone:        +420 222745111
fax-no:       +420 222745112
e-mail:       admin@nic.cz

contact:      technical
name:         Martin Peterka
organisation: CZ.NIC, z.s.p.o.
address:      Milesovska 5
address:      Prague 130 00
address:      Czechia
phone:        +420 222745111
fax-no:       +420 222745112
e-mail:       tech@nic.cz

nserver:      A.NS.NIC.CZ 194.0.12.1 2001:678:f:0:0:0:0:1
nserver:      B.NS.NIC.CZ 194.0.13.1 2001:678:10:0:0:0:0:1
nserver:      C.NS.NIC.CZ 194.0.14.1 2001:678:11:0:0:0:0:1
nserver:      D.NS.NIC.CZ 193.29.206.1 2001:678:1:0:0:0:0:1
ds-rdata:     20237 13 2 cff0f3ecdbc529c1f0031ba1840bfb835853b9209ed1e508fff48451d7b778e2

whois:        whois.nic.cz

status:       ACTIVE
remarks:      Registration information: http://www.nic.cz/

created:      1993-01-13
changed:      2023-03-07
source:       IANA