Convert internationalized domain names (IDN) to ASCII xn-- Punycode and vice-versa.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Choose Unicode to Punycode or Punycode to Unicode decoding mode.
Paste one or multiple domain names (one per line) into the input box.
Copy the RFC 3492 compliant Punycode or Unicode domain list with 1-click.
Punycode is an encoding syntax defined in RFC 3492 that translates Unicode characters into the limited ASCII character set supported by the global Domain Name System (DNS).
Punycode encoded domain labels always start with the prefix 'xn--' (for example, münchen.de becomes xn--mnchen-3ya.de).
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