Converts internationalized domain names and emails: Unicode labels become ASCII with xn-- prefixes; decode reverses that.
Converts internationalized domain names and emails: Unicode labels become ASCII with xn-- prefixes; decode reverses that.
Punycode / IDN
Convert domain names and email addresses with non-ASCII labels to Punycode (ASCII with xn-- prefixes) and back. Handles multiple labels and @-separated mailboxes locally in your browser. Large inputs run in a Web Worker.
Punycode / IDN Use Cases
- Preview how a Unicode hostname or email domain will look in DNS (xn-- form) before configuring DNS or mail
- Decode xn-- hostnames from logs, certificates, or browser devtools back to readable Unicode
- Batch-convert IDN examples in documentation, slides, or support tickets
- Debug URL and email handling when mixing ASCII and internationalized labels
Punycode / IDN FAQ
Is my domain or email sent to a server?
No. Conversion uses the Punycode library entirely in your browser. Your strings never leave your device.
What does “encode” do here?
Encode runs IDNA toASCII: each label with non-ASCII characters becomes ASCII with an xn-- prefix. Plain ASCII labels are left unchanged.
Does this validate real DNS registration rules?
It applies Punycode conversion per RFC 3492 / 5891-style behavior. Full UTS #46 domain registration checks (mapping, validation) are beyond this tool—use registrar or specialized libraries for that.
Why use a Web Worker for large input?
Inputs over 500KB are processed off the main thread so typing, scrolling, and controls stay responsive.