XML (Extensible Markup Language) was the king of data exchange before JSON arrived. While many consider it a legacy usage, XML is still the backbone of enterprise systems, SOAP APIs, RSS feeds, SVG vector graphics, and Android layouts.

The problem? XML is verbose. A single SOAP response can be thousands of characters long with no line breaks, making it impossible to read. The XML Formatter parses this "wall of text" and returns a structured, indented tree.

Why XML is Still Relevant

  • Strict Schema: Unlike JSON, XML can be strictly validated against an XSD (XML Schema Definition).
  • Metadata: XML allows complex attributes on tags, creating a rich data description layer `<price currency="USD">10</price>`.
  • Namespaces: The `xmlns` feature prevents naming collisions when combining multiple data sources.

Common XML Syntax Pitfalls

Parsing XML is stricter than HTML. Small errors cause the parser to fail completely. Our tool highlights these errors:

1. Unclosed Tags

<user>
  <name>John
</user> ❌ Error: Missing </name>

2. Case Sensitivity

`<Tag>` and `<tag>` are different elements in XML.

3. Root Element

A valid XML document must have exactly one root element. You cannot simply list users; you must wrap them in a `<users>` list tag.

Attributes vs Elements

One of the biggest design choices in XML is whether to put data in an attribute or a child element.

<!-- Attribute Style -->
<book id="123" title="Harry Potter" />

<!-- Element Style (More expansible) -->
<book>
  <id>123</id>
  <title>Harry Potter</title>
</book>

Our formatter handles both gracefully, ensuring attributes are aligned for readability.

Moving to modern APIs? Convert your data using our XML to JSON Converter.