International Domains

Internationalized Domain Names (IDN)

Originally, the Domain Name System (DNS) standard only allowed domain names made up of ASCII characters. These characters consisted of the 26 Latin letters (a-z), digits (0-9) and a hyphen (-) — 37 characters in total.

However, as the number of users of languages based on non-Latin alphabets grew, a decision was made to allow domain names containing Unicode characters to be registered. This led to the emergence of multilingual domain names — Internationalized Domain Names (IDN).

To let DNS support IDNs, a standard method called Punycode was developed. This method converts Unicode characters into ASCII format. So that IDN domain names aren't confused with regular domain names, every IDN domain converted to Punycode format begins with a special "XN--" prefix. For example, the domain "россия.рф" becomes "xn--h1alffa9f.xn--p1ai" in Punycode format.

The browser converts the IDN domain to Punycode and to ASCII format to interact with DNS. When a user types an IDN domain into the address bar, the browser automatically converts it and communicates with DNS, making multilingual domain names usable.

IDN domains make websites more accessible in a variety of languages and provide an important convenience for internet users worldwide.