Enter a domain with non-Latin characters to get its Punycode form — the xn-- name that DNS, certificates and server configs actually use — or paste an xn-- name to see what it says.
Runs entirely in your browser — nothing you enter here is sent to a server.
The Domain Name System was built for a tiny alphabet: the letters a–z, the digits and the hyphen. An internationalized domain name (IDN) lets a name contain other characters — münchen.de, пример.рф, 例え.jp — without changing DNS itself. The trick is an encoding called Punycode, which rewrites each non-ASCII label using only the allowed characters and marks it with the prefix xn--.
So münchen.de is what people see, and xn--mnchen-3ya.de is what is actually registered, looked up and written into certificates. Browsers translate between the two silently. Everything else — DNS zone files, web server configuration, TLS certificates, email settings, firewalls, monitoring — works with the ASCII form, and that is when you need a converter.
server_name in nginx, ServerName in Apache and most control panels expect the xn-- form.
A certificate request and a DNS record for an IDN must use the Punycode name; the Unicode spelling will not match.
Access logs, dig output and email headers show xn-- names. Paste them here to see which site they refer to.
Only the parts between dots that contain non-ASCII characters are encoded. In shop.münchen.de, only the middle label changes.
Unicode contains many characters that look identical to Latin letters: the Cyrillic "а", "е", "о", "р", "с" are indistinguishable from their Latin twins in most fonts. A domain that mixes them — аpple.com with a Cyrillic first letter — looks legitimate and leads somewhere else entirely. This is a homograph attack, and it is a standard phishing technique.
The converter flags any label that mixes alphabets. Browsers defend against the same thing by displaying such names in their raw xn-- form. If a link in an email turns out to be an xn-- domain you did not expect, converting it shows exactly which characters it really contains — and whether it is the site it pretends to be.
An encoding defined in RFC 3492 that represents Unicode text using only ASCII letters, digits and hyphens. Domain labels encoded with it start with xn--, for example xn--mnchen-3ya for münchen.
That the label is an internationalized name encoded in Punycode. Decoding it gives the Unicode characters the owner registered.
The Punycode form. Web servers, DNS zones, certificate requests and mail configuration generally require the ASCII xn-- name.
The technology is. The risk is look-alike names that mix alphabets to imitate a known brand. Check the Punycode form of any unexpected link, and be wary of names flagged as mixed-script.
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