Punycode / IDN Converter

DNS was designed back when nobody pictured a domain written in Japanese or Russian. It only understands ASCII letters, digits and hyphens. For "café.com.br" to work anyway, there is IDNA: before the name goes out on the wire, it gets translated into an equivalent ASCII form, always starting with xn--. That is why café.com.br becomes xn--caf-dma.com.br and ПРИМЕР.РФ becomes xn--e1afmkfd.xn--p1ai.

Here you type the domain the way a person sees it and get back the form the name servers actually use. The conversion is done by the browser itself, with the same IDNA implementation it applies when you type an address in the bar — normalization included, which lowercases and folds equivalent characters before encoding. Each label between dots is encoded on its own, and labels that are already ASCII pass through untouched.

The road here runs one way: paste an xn-- and you get the same xn-- back, because that already is the ASCII form. Where it earns its keep is in filling fields that reject accented characters — certificate SANs, zone records, firewall allowlists, SPF configuration — and in comparing lookalike domains, since two names that look identical on screen can have completely different punycode forms.