JSON to XML: How Objects, Arrays, and Attributes Get Mapped

Objects Become Elements

Each key in a JSON object typically becomes an XML element with that key as its tag name, and the corresponding value becomes that element's content — either text, for primitive values, or nested child elements, if the value is itself an object.

// JSON
{ "user": { "name": "Alex", "age": 30 } }

<!-- XML -->
<user>
  <name>Alex</name>
  <age>30</age>
</user>

Arrays Become Repeated Tags

Since XML has no native concept of an array, a JSON array is typically represented as multiple sibling elements sharing the same tag name — one per array item. A converter has to decide what to call these repeated elements, since JSON arrays don't carry a name for their individual items the way object keys do.

// JSON
{ "tags": ["admin", "editor"] }

<!-- XML -->
<tags>
  <item>admin</item>
  <item>editor</item>
</tags>

Where Attributes Come From

Plain JSON has no direct equivalent of an XML attribute — everything is just a key-value pair. Converters commonly use a naming convention, such as a leading @ on a key, to signal that a particular value should become an XML attribute rather than a child element. If your source JSON doesn't already follow such a convention, expect the converter to default to representing every key as a nested element rather than guessing which ones "should" be attributes.

Why This Matters When You're Not Just Eyeballing the Output

If the XML you're generating needs to match a specific schema or an existing system's expectations, these mapping decisions aren't just cosmetic — a system expecting an attribute won't recognize the same data represented as a child element, even though both are valid XML. Understanding how your converter makes these choices helps you catch mismatches before they cause an integration to fail downstream.