Punycode is a sequence of ASCII characters that all IDNs will be encoded into in order for the Domain Name System (DNS) to understand and manage the names.

The intention is that domain name registrants and user will never see this decoded form of a domain name.

It is an algorithm that uniquely and reversibly transforms Unicode strings into the limited character set supported by the DNS. A converted IDN contains only IRA (International Reference Alphabet) characters and starts with the “xn--” prefix.

Example: