Punycode & IDN Domain Converter

Internationalized Domain Names (IDN) allow domain names to be written in non-ASCII scripts including Cyrillic, Arabic, Chinese, Devanagari, Korean, Japanese and many others. Punycode is the ASCII-compatible encoding (ACE) algorithm defined in RFC 3492 that converts these characters into a format compatible with the existing DNS infrastructure.

How Punycode Works

Punycode labels are prefixed with "xn--" followed by the ASCII-compatible representation of the Unicode string. For example, the Russian domain "яндекс.рф" becomes "xn--d1acpjx3f.xn--p1ai". The full domain is called an A-label (ASCII label) and the original Unicode version is the U-label.

Examples

• яндекс.рф → xn--d1acpjx3f.xn--p1ai (Yandex Russia)
• münchen.de → xn--mnchen-3ya.de (Munich, Germany)
• مثال.إختبار → xn--mgbh0fb.xn--kgbechtv (Arabic example)
• 例え.jp → xn--r8jz45g.jp (Japanese example)

Why IDN Matters for Security

IDN homograph attacks exploit the visual similarity between characters from different scripts. For example, a Cyrillic "а" (U+0430) looks identical to a Latin "a" (U+0061). Attackers register look-alike domains to conduct phishing. Modern browsers display the Punycode form for suspicious IDN domains to warn users. Always verify the true domain in your browser's address bar.