Punycode Converter

Punycode is a special encoding system defined in RFC 3492 that converts Unicode (international) characters into the limited ASCII character set allowed for domain names. It is the foundation of Internationalized Domain Names (IDN), enabling domain names with non-ASCII characters like münchen.de, café.fr, or δοκιμή.gr.

Punycode-encoded domains are prefixed with xn--. For example, münchen.de becomes xn--mnchen-3ya.de. The xn-- prefix tells browsers and DNS systems that the label uses Punycode encoding.

Why Punycode Matters

• Enables domain names in native scripts (Arabic, Chinese, Cyrillic, etc.)
• Critical for DNS compatibility — DNS only understands ASCII
• Prevents homograph attacks by revealing actual encoded domain
• Required by all modern browsers for IDN support

1. Encode to Punycode — Type or paste a Unicode domain name or URL in the left panel (e.g., münchen.de), then click Encode.
2. Decode from Punycode — Type or paste a Punycode domain in the right panel (e.g., xn--mnchen-3ya.de), then click Decode.
3. Supports full URLs — You can paste complete URLs like https://münchen.de/path?q=1 and only the domain portion will be encoded.
4. Swap & Clear — Click Swap to exchange encode/decode values, Clear All to reset everything.

• Domain registration — Check how your international domain name looks in Punycode before registering it.
• Security auditing — Decode Punycode domains to detect homograph attacks where lookalike characters are used to impersonate legitimate domains.
• DNS configuration — Convert Unicode domain names to Punycode for DNS zone files and web server configuration.
• Email client setup — Configure email clients with international domain names by converting them to Punycode.
• Browser testing — Verify that your web application correctly handles IDN domain names in URLs and redirects.