Why IDN Matters
Over 60% of world internet users are non-English speakers. Internationalized Domain Names (IDN) allow native scripts—café.com, 中国.cn, москва.рф—making the web more accessible and brandable locally.
Unicode vs ASCII Conflict
DNS was built on ASCII only. To preserve backward compatibility, IDN converts Unicode to ASCII using Punycode (RFC 3492). Example: müller.com → xn--mller-kva.com.
Registration Workflow
- User enters native script at registrar
- Registrar validates against allowed code table per TLD
- String converted to Punycode
- Punycode stored in registry EPP and DNS
Language Tables & Policy
Each TLD publishes allowed Unicode ranges. .com permits most Latin, Cyrillic, Arabic, CJK, but blocks mixed-script like “paypal” + Cyrillic “a” (homograph attack). .eu bans Greek + Latin in same label.
Homograph Spoofing Defense
Registries maintain variant blocks: if you own bank.com in Cyrillic, you get Latin look-alike for free to prevent phishing. Browsers show Punycode in address bar when mixed scripts detected.
SEO & User Experience
Google ranks IDN same as ASCII provided content matches user language. Display URLs in SERPs show Unicode, increasing CTR for local queries. Ensure your CMS supports UTF-8 slugs to avoid 404s.
Email Compatibility
SMTP still prefers ASCII; use Punycode in MX records. Modern mail servers (Gmail, Outlook) accept Unicode headers, but fallback to Punycode guarantees delivery to legacy MTAs.
Market Value
Premium Chinese numeric .cn and German umlaut .de trade for 5-6 figures locally. Liquidity is lower than ASCII, but end-user demand is strong—especially for category killers like Casino.de or 保险.com (“insurance”).
Implementation Tips
- Register both with- and without-accent versions if available
- Use HTTPS cert with Unicode SAN field
- Canonical tag should use Unicode, not Punycode
- Test in multiple browsers; older versions may display raw Punycode
Future Outlook
ICANN is evaluating universal acceptance initiatives to push email, SSL, and mobile apps toward full IDN support. Early adopters who secure quality names now may enjoy first-mover premiums.