What encoding converts emoji in domain names into ASCII labels?

Punycode is the encoding that converts emoji in domain names into ASCII labels. Domain Name System labels traditionally use a restricted ASCII character set, so emoji and other non-ASCII characters need a compatible representation before they can be registered and resolved.

Punycode was designed for internationalized domain names (IDNs). The resulting ASCII form normally begins with “xn--” and encodes the original Unicode characters after that marker. For example, the emoji 😉 is represented as xn--n28h in an IDN.

Punycode is not the same as Base64, ASCII85, or Morse code. Those are unrelated encoding or signaling systems: Base64 and ASCII85 package binary data as text, while Morse code represents letters and symbols as timed signals. Punycode specifically supports Unicode domain labels.

Emoji domains remain subject to registry, browser, and security limitations. Some browsers display the ASCII form, and visually similar emoji can create confusion or phishing risks.