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Encoding / LOCAL TOOL

Punycode / IDN Converter

Convert internationalized domain names between Unicode and ASCII Punycode locally.

Runs locally — input is never uploaded
Enter a domain name
Ready when you are

WHAT IT DOES

Read the Unicode domain and the ASCII label it travels as.

Convert a domain name to ASCII-compatible Punycode or back to Unicode without contacting DNS or a remote IDN service. Auto mode reads an xn-- label as Punycode and a regular internationalized label as Unicode, while the result states which direction was detected.

Why use it?

Use it to compare an internationalized hostname's Unicode spelling with its ASCII-compatible labels, especially when reviewing links or domain configuration.

How to use this tool

  1. Enter the hostname only, without a scheme, path, email username, or query, then convert.
  2. Check the reported direction. For example, bücher.example converts to xn--bcher-kva.example.
  3. Inspect the actual labels rather than relying on visual similarity. Conversion does not establish registration, reachability, ownership, or trust.

Details and limitations

  • The converter handles domain labels rather than paths, query strings, email addresses, or arbitrary text, so an accidental URL is reported clearly.
  • Each label and the complete domain are checked against DNS-compatible length limits before and after conversion.
  • Punycode conversion is deterministic and uses the browser-safe local library bundled with the application.
  • This tool converts spelling; it does not resolve the domain, validate ownership, or judge whether a lookalike domain is trustworthy.

WORKED EXAMPLES

Compare both spellings of an internationalized label

Convert this Unicode hostname, then convert the ASCII result back. The reserved example domain is used to demonstrate spelling, not a network lookup.

Hostname

bücher.example

Expected result

xn--bcher-kva.example, which converts back to bücher.example. The ASCII spelling makes the encoded label visible; neither form establishes that a site is trustworthy.

COMMON QUESTIONS

Punycode questions

Does this check whether a domain exists?
No. It only converts the label representation. It does not resolve DNS, contact the domain, verify ownership, or assess whether the Unicode spelling is a homograph risk.
What does xn-- mean?
xn-- is the ASCII prefix used for an internationalized DNS label encoded with Punycode. Auto mode uses that marker to choose the Punycode-to-Unicode direction.