Nested JSON Objects to XML Elements

Nested objects are where XML's hierarchical nature aligns well with JSON's nested structure. Each level of JSON nesting maps to a level of XML element nesting.

A nested JSON object:

{
  "company": {
    "name": "Acme Corp",
    "address": {
      "street": "123 Main St",
      "city": "Springfield",
      "state": "IL"
    },
    "contact": {
      "phone": "555-0100",
      "email": "info@acme.com"
    }
  }
}

The XML equivalent:

<company>
  <name>Acme Corp</name>
  <address>
    <street>123 Main St</street>
    <city>Springfield</city>
    <state>IL</state>
  </address>
  <contact>
    <phone>555-0100</phone>
    <email>info@acme.com</email>
  </contact>
</company>

How nesting translates:

1. Each JSON object becomes a parent element. The key "address" becomes <address>, and its child keys become child elements.
2. Depth is unlimited. Both JSON and XML support arbitrary nesting depth. However, very deep structures (10+ levels) become hard to read in both formats.
3. Order is preserved differently. JSON object keys technically have no guaranteed order (though modern engines preserve insertion order). XML elements have explicit document order.

Key differences:

• XML requires unique element context. While JSON allows duplicate keys (last one wins in most parsers), XML allows sibling elements with the same name, which maps to arrays in JSON.
• Empty objects ({}) in JSON can map to empty elements (<address/>) or self-closing tags in XML.
• Mixed nesting patterns (some keys are objects, others are primitives) convert naturally, as XML freely mixes text-only elements with elements containing children.

When converting XML back to JSON, the parser must determine whether each element with children represents an object (unique child names) or an array (repeated child names). This heuristic is the most common source of round-trip conversion errors.