XML Processing in the Modern Web

XML Processing in the Modern Web

XML may seem like a relic, but it's still everywhere: RSS feeds, SOAP APIs, SVG images, XHTML, Android layouts, Maven configs, and countless enterprise integrations.

When You'll Encounter XML

RSS/Atom feeds — blog syndication, podcast feeds

SOAP APIs — enterprise integrations, payment gateways

SVG — scalable vector graphics are XML

Configuration — Maven pom.xml, .NET .csproj, Android manifests

Data exchange — banking (SWIFT), healthcare (HL7), government APIs

Parsing XML in JavaScript

DOMParser (Browser)

const parser = new DOMParser();
const doc = parser.parseFromString(xmlString, "text/xml");
const title = doc.querySelector("title")?.textContent;

Fast-xml-parser (Node.js)

import { XMLParser } from "fast-xml-parser";
const parser = new XMLParser({ ignoreAttributes: false });
const result = parser.parse(xmlString);

XML vs JSON Conversion

Converting between XML and JSON is common but lossy. Key challenges:

Attributes vs elements — XML has both; JSON has neither. Convention: prefix attributes with @.

Arrays — single child elements look like objects, not arrays. Parsers need hints.

Mixed content —

Hello world

has no clean JSON equivalent.

Namespaces — XML namespaces don't map naturally to JSON.

Formatting XML

Readable XML uses consistent indentation:

  
    
    David Thomas
    49.99
  

Use our XML Formatter to beautify, indent, or minify XML documents instantly.

XPath

XPath is the query language for XML, similar to JSONPath for JSON:

//book[@id='1']/title    → selects the title of book with id=1
//book[price > 30]       → selects books costing more than 30
//book/author/text()     → selects all author text nodes

Conclusion

XML isn't going away. Know how to parse it, convert it, and format it. Use the right tool for the job — DOMParser in browsers, fast-xml-parser or xml2js in Node.