JSON vs XML — What Is the Difference?

The short answer

Both JSON and XML are text-based formats for representing structured data. JSON is lighter, easier to read, and dominates modern web APIs. XML is more powerful, more verbose, and still widely used in enterprise systems, document formats, and anywhere its richer feature set is needed.

For most new projects building REST APIs or exchanging data between web services, JSON is the default choice. XML is chosen when you need something specific it provides.

Side-by-side example

The same data in both formats:

{
  "user": {
    "id": 1,
    "name": "Jane Smith",
    "email": "jane@example.com",
    "roles": ["admin", "editor"],
    "active": true
  }
}

<user>
  <id>1</id>
  <name>Jane Smith</name>
  <email>jane@example.com</email>
  <roles>
    <role>admin</role>
    <role>editor</role>
  </roles>
  <active>true</active>
</user>

The JSON version is ~30% smaller and easier to scan. The XML version is more explicit about structure and can be extended with attributes and namespaces.

Feature comparison

When to use JSON

• REST APIs — it's the universal default
• Configuration files (package.json, tsconfig.json etc.)
• Browser-to-server communication
• NoSQL databases (MongoDB, Firestore store documents as JSON)
• Any context where file size or parse speed matters

When to use XML

• SOAP web services — XML is mandatory
• Document formats — DOCX, XLSX, SVG, and RSS are all XML under the hood
• Enterprise systems that rely on XML tooling (XSLT transforms, XPath queries)
• Android app manifests and Maven build files
• Sitemaps — the format Google uses is XML
• When you need comments in your data format

Is XML dying?

No. JSON has largely replaced XML for web APIs, but XML is deeply embedded in enterprise infrastructure, document standards, and tooling that will run for decades. The better framing is that JSON won the web API space, while XML retained everything it was already good at.