Punycode Converter
Punycode and IDN Domain Converter
Convert internationalized domain names (IDN) to Punycode (xn-- form) and back, following RFC 3492.
About Punycode
Punycode is an encoding defined in RFC 3492 that represents Unicode characters using only the limited ASCII set allowed in host names (letters, digits, and hyphen). It lets internationalized domain names (IDN), such as münchen.de or 例え.jp, work with the existing DNS infrastructure, which only understands ASCII. Each label of a domain that contains non-ASCII characters is converted separately and prefixed with xn--, so münchen.de becomes xn--mnchen-3ya.de.
Punycode is a special instance of the Bootstring algorithm with the parameters base 36, tmin 1, tmax 26, skew 38, damp 700, initial bias 72, and initial n 128. It works by listing the plain ASCII characters first, then encoding the positions and code points of the non-ASCII characters as a series of generalized variable-length integers with an adaptive bias. Browsers display the Unicode form to users but send the Punycode form over the network.
