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Punycode Encoder/Decoder

Convert IDN domains (with accents or non-ASCII characters) to Punycode (xn--...) and back. Useful for registering international domains and validating emails. Everything in your browser.

What is Punycode?

Punycode (RFC 3492) is a way of writing domain names that contain non-ASCII characters (accents, ideographs, emoji) using nothing but the letters a–z, digits and hyphens. The result always carries the xn-- prefix.

It is how café.com turns into xn--caf-dma.com on DNS servers. Browsers run this conversion internally whenever you open an IDN (Internationalized Domain Name).

Use this tool to register international domains, check IDN e-mail addresses, or inspect a suspicious URL — homograph scams routinely abuse Unicode characters that look identical to Latin letters. Everything runs in your browser.

What that xn-- in a domain means

You registered a domain with accented characters and it shows up as xn--something in DNS or on the certificate. Or you received a suspicious link starting with xn-- and want to see which characters it actually hides. This page converts both ways, Unicode to Punycode and back, with a ready-made example one click away and live results as you type.

DNS only accepts ASCII letters, digits and hyphens. Punycode (RFC 3492) works around that by encoding the special characters into a suffix: café.com becomes xn--caf-dma.com, where 'caf' is the plain letters and 'dma' encodes the position and value of the é. Each label (the part between dots) is converted separately, and labels that are already ASCII stay untouched. On encoding, the label is lowercased, since DNS ignores case anyway.

Use the xn-- form when configuring DNS zones and TLS certificates, which store the ASCII name. Use decoding to unmask homograph phishing: a Cyrillic 'a' looks identical to the Latin one but produces a different xn--. If a well-known domain shows up encoded, be suspicious. Invalid punycode shows an error message instead of silent garbage. Everything converts right in your browser.

Frequently asked questions

Why does my accented domain turn into xn-- on the certificate?
Because DNS and certificates only store ASCII. The actually registered name is the xn-- form; your browser is what displays the pretty Unicode version.
Can I register an emoji domain?
Punycode encodes emoji just fine, but most registries reject them. A few country TLDs, such as .ws, do allow emoji domains.
How do I check a suspicious link with this?
Paste the link's domain in Unicode to Punycode mode. If a name that should be plain ASCII produces an xn--, it contains lookalike characters and is probably a scam.

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