| # Punycode.js [](https://travis-ci.org/bestiejs/punycode.js) [](https://codecov.io/gh/bestiejs/punycode.js) [](https://gemnasium.com/bestiejs/punycode.js) | 
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 | Punycode.js is a robust Punycode converter that fully complies to [RFC 3492](https://tools.ietf.org/html/rfc3492) and [RFC 5891](https://tools.ietf.org/html/rfc5891). | 
 |  | 
 | This JavaScript library is the result of comparing, optimizing and documenting different open-source implementations of the Punycode algorithm: | 
 |  | 
 | * [The C example code from RFC 3492](https://tools.ietf.org/html/rfc3492#appendix-C) | 
 | * [`punycode.c` by _Markus W. Scherer_ (IBM)](http://opensource.apple.com/source/ICU/ICU-400.42/icuSources/common/punycode.c) | 
 | * [`punycode.c` by _Ben Noordhuis_](https://github.com/bnoordhuis/punycode/blob/master/punycode.c) | 
 | * [JavaScript implementation by _some_](http://stackoverflow.com/questions/183485/can-anyone-recommend-a-good-free-javascript-for-punycode-to-unicode-conversion/301287#301287) | 
 | * [`punycode.js` by _Ben Noordhuis_](https://github.com/joyent/node/blob/426298c8c1c0d5b5224ac3658c41e7c2a3fe9377/lib/punycode.js) (note: [not fully compliant](https://github.com/joyent/node/issues/2072)) | 
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 | This project was [bundled](https://github.com/joyent/node/blob/master/lib/punycode.js) with Node.js from [v0.6.2+](https://github.com/joyent/node/compare/975f1930b1...61e796decc) until [v7](https://github.com/nodejs/node/pull/7941) (soft-deprecated). | 
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 | The current version supports recent versions of Node.js only. It provides a CommonJS module and an ES6 module. For the old version that offers the same functionality with broader support, including Rhino, Ringo, Narwhal, and web browsers, see [v1.4.1](https://github.com/bestiejs/punycode.js/releases/tag/v1.4.1). | 
 |  | 
 | ## Installation | 
 |  | 
 | Via [npm](https://www.npmjs.com/): | 
 |  | 
 | ```bash | 
 | npm install punycode --save | 
 | ``` | 
 |  | 
 | In [Node.js](https://nodejs.org/): | 
 |  | 
 | ```js | 
 | const punycode = require('punycode'); | 
 | ``` | 
 |  | 
 | ## API | 
 |  | 
 | ### `punycode.decode(string)` | 
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 | Converts a Punycode string of ASCII symbols to a string of Unicode symbols. | 
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 | ```js | 
 | // decode domain name parts | 
 | punycode.decode('maana-pta'); // 'mañana' | 
 | punycode.decode('--dqo34k'); // '☃-⌘' | 
 | ``` | 
 |  | 
 | ### `punycode.encode(string)` | 
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 | Converts a string of Unicode symbols to a Punycode string of ASCII symbols. | 
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 | ```js | 
 | // encode domain name parts | 
 | punycode.encode('mañana'); // 'maana-pta' | 
 | punycode.encode('☃-⌘'); // '--dqo34k' | 
 | ``` | 
 |  | 
 | ### `punycode.toUnicode(input)` | 
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 | Converts a Punycode string representing a domain name or an email address to Unicode. Only the Punycoded parts of the input will be converted, i.e. it doesn’t matter if you call it on a string that has already been converted to Unicode. | 
 |  | 
 | ```js | 
 | // decode domain names | 
 | punycode.toUnicode('xn--maana-pta.com'); | 
 | // → 'mañana.com' | 
 | punycode.toUnicode('xn----dqo34k.com'); | 
 | // → '☃-⌘.com' | 
 |  | 
 | // decode email addresses | 
 | punycode.toUnicode('джумла@xn--p-8sbkgc5ag7bhce.xn--ba-lmcq'); | 
 | // → 'джумла@джpумлатест.bрфa' | 
 | ``` | 
 |  | 
 | ### `punycode.toASCII(input)` | 
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 | Converts a lowercased Unicode string representing a domain name or an email address to Punycode. Only the non-ASCII parts of the input will be converted, i.e. it doesn’t matter if you call it with a domain that’s already in ASCII. | 
 |  | 
 | ```js | 
 | // encode domain names | 
 | punycode.toASCII('mañana.com'); | 
 | // → 'xn--maana-pta.com' | 
 | punycode.toASCII('☃-⌘.com'); | 
 | // → 'xn----dqo34k.com' | 
 |  | 
 | // encode email addresses | 
 | punycode.toASCII('джумла@джpумлатест.bрфa'); | 
 | // → 'джумла@xn--p-8sbkgc5ag7bhce.xn--ba-lmcq' | 
 | ``` | 
 |  | 
 | ### `punycode.ucs2` | 
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 | #### `punycode.ucs2.decode(string)` | 
 |  | 
 | Creates an array containing the numeric code point values of each Unicode symbol in the string. While [JavaScript uses UCS-2 internally](https://mathiasbynens.be/notes/javascript-encoding), this function will convert a pair of surrogate halves (each of which UCS-2 exposes as separate characters) into a single code point, matching UTF-16. | 
 |  | 
 | ```js | 
 | punycode.ucs2.decode('abc'); | 
 | // → [0x61, 0x62, 0x63] | 
 | // surrogate pair for U+1D306 TETRAGRAM FOR CENTRE: | 
 | punycode.ucs2.decode('\uD834\uDF06'); | 
 | // → [0x1D306] | 
 | ``` | 
 |  | 
 | #### `punycode.ucs2.encode(codePoints)` | 
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 | Creates a string based on an array of numeric code point values. | 
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 | ```js | 
 | punycode.ucs2.encode([0x61, 0x62, 0x63]); | 
 | // → 'abc' | 
 | punycode.ucs2.encode([0x1D306]); | 
 | // → '\uD834\uDF06' | 
 | ``` | 
 |  | 
 | ### `punycode.version` | 
 |  | 
 | A string representing the current Punycode.js version number. | 
 |  | 
 | ## Author | 
 |  | 
 | | [](https://twitter.com/mathias "Follow @mathias on Twitter") | | 
 | |---| | 
 | | [Mathias Bynens](https://mathiasbynens.be/) | | 
 |  | 
 | ## License | 
 |  | 
 | Punycode.js is available under the [MIT](https://mths.be/mit) license. |