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Validate XML or Parse XML to JS/JSON very fast without C/C++ based libraries and no callback

You can use this library online (press try me button above), or as command from CLI, or in your website, or in npm repo.

  • This library let you validate the XML data syntactically.
  • Or you can transform/covert/parse XML data to JS/JSON object.
  • Or you can transform the XML in traversable JS object which can later be converted to JS/JSON object.

Code Climate Stubmatic donate button Donate using Liberapay Known Vulnerabilities Travis ci Build Status Coverage Status Try me bitHound Dev Dependencies bitHound Overall Score NPM total downloads

How to use


$npm install fast-xml-parser

or using yarn

$yarn add fast-xml-parser


var fastXmlParser = require('fast-xml-parser');
var jsonObj = fastXmlParser.parse(xmlData);
// when a tag has attributes
var options = {
    attrPrefix : "@_",
    attrNodeName: false,
    textNodeName : "#text",
    ignoreNonTextNodeAttr : true,
    ignoreTextNodeAttr : true,
    ignoreNameSpace : true,
    ignoreRootElement : false,
    textNodeConversion : true,
    textAttrConversion : false,
    arrayMode : false
if(fastXmlParser.validate(xmlData)=== true){//optional
    var jsonObj = fastXmlParser.parse(xmlData,options);
//Intermediate obj
var tObj = fastXmlParser.getTraversalObj(xmlData,options);
var jsonObj = fastXmlParser.convertToJson(tObj);

To use from command line

$xml2js [-ns|-a|-c] <filename> [-o outputfile.json]
$cat xmlfile.xml | xml2js [-ns|-a|-c] [-o outputfile.json]

-ns : To include namespaces (bedefault ignored) -a : To ignore attributes -c : To ignore value conversion (i.e. "-3" will not be converted to number -3)

To use it on webpage

  1. Download and include parser.js
var isValid = parser.validate(xmlData);
var jsonObj = parser.parse(xmlData);


I decided to created this library when I couldn't find any library which can convert XML data to json without any callback and which is not based on any C/C++ library.

Libraries that I compared

  • xml-mapping : fast, result is not satisfactory
  • xml2js : fast, result is not satisfactory
  • xml2js-expat : couldn't test performance as it gives error on high load. Installation failed on travis and on my local machine using 'yarn'.
  • xml2json : based on node-expat which is based on C/C++. Installation failed on travis.
  • fast-xml-parser : very very fast.

Why not C/C++ based libraries? Installation of such libraries fails on some OS. You may require to install missing dependency manually.

Benchmark report


Don't forget to check the performance report on comparejs.

validator benchmark: 21000 tps


  • Parser doesn't check if the XML is valid or not. If the XML is not valid you may get invalid result. So you can call the validator function first to check the structure.
  • This is based on JS regular expression engine. So due to it's limitation fast-xml-parser face performance issue when it process XML string(data) which is very large like 10mb or more. (I'll look into this as soon as I get some free time). UPDATE: from v2.9.0, I have rewritten the validator code. So that validator can handle large files as well. I have tested it up to 98mb xml file. I have some more ideas to increase the speed. And I'll work whenever I get the time.

Report an issue or request for a feature here

Your contribution in terms of donation, testing, bug fixes, code development etc. can help me to write fast algorithms. Stubmatic donate button

Give me a star, if you really like this project.

Fund collected (since the starting of the project) : $0

Some of my other NPM pojects

  • stubmatic : A stub server to mock behaviour of HTTP(s) / REST / SOAP services. Stubbing redis is on the way.
  • compare js : compare the features of JS code, libraries, and NPM repos.
  • fast-lorem-ipsum : Generate lorem ipsum words, sentences, paragraph very quickly.


  • P2: parser online demo with more options
  • P2: validator cli
  • P2: fast XML prettyfier