XML vs JSON: Which Data Format Wins?

XML vs JSON: A Modern Comparison

XML dominated data exchange in the early web era. JSON took over in the 2010s with the rise of REST APIs. But XML is far from dead — it's still the backbone of enterprise systems, document formats, and standards like SVG and RSS. Understanding both helps you work with legacy systems and choose the right format for new projects.

Syntax Comparison

The same "user" object in both formats:

<!-- XML -->
<user>
  <name>Alice</name>
  <age>30</age>
  <active>true</active>
</user>

// JSON
{
  "name": "Alice",
  "age": 30,
  "active": true
}

Head-to-Head

Feature	XML	JSON
Verbosity	High (opening/closing tags)	Low
Data types	Strings only (needs schema)	String, number, bool, null, array
Attributes	Yes (element attributes)	No (all key-value pairs)
Comments	Yes	No
Schema validation	XSD, DTD (powerful)	JSON Schema (less mature)
Namespace support	Yes	No
Browser parse	DOMParser	JSON.parse (faster)
File size	Larger	Smaller
REST API default	No	Yes

Where XML Still Wins

• Document formats — Microsoft Office files (.docx, .xlsx) are XML archives. SVG images are XML.
• Enterprise integrations — SOAP web services, SAP, and many banking/insurance systems use XML.
• RSS and Atom feeds — Still XML-based standards.
• Strict schema validation — XSD schemas for XML are more mature and expressive than JSON Schema.
• Mixed content — XML can contain text mixed with markup elements, like HTML.

Where JSON Wins

• REST APIs — virtually all modern web APIs use JSON
• JavaScript applications — no parsing library needed
• NoSQL databases — MongoDB, Firebase store JSON natively
• Mobile apps — smaller payload means faster API responses
• Configuration files — more human-friendly than XML

Working with XML

Format and validate your XML with Utilko's free XML Formatter, or convert XML to JSON with the XML to JSON Converter.