A pure Erlang IDNA implementation.
1> Domain = unicode:characters_to_list("www.詹姆斯.com").
...
2> idna:to_ascii(Domain).
...RFC3490 (IDNA)
RFC3492 (Punycode)
addressable (Ruby URI implementation)
punycode4r (Ruby punycode implementation)
UAX #15 (Unicode Normalization Forms)