XML Formatter

XML uses tags with opening and closing elements while JSON uses key-value pairs with curly braces. XML supports attributes, namespaces, and mixed content, making it more expressive but more verbose. JSON is lighter, easier to parse in JavaScript, and dominant in web APIs. XML remains prevalent in enterprise systems, configuration files, and document formats like SVG and XHTML.

Well-formed XML requires: a single root element, properly nested tags (every opening tag must have a matching closing tag), case-sensitive tag names, quoted attribute values, and proper character escaping for special characters (&, <, >, ", '). Valid XML additionally conforms to a DTD or XML Schema.

Well-formed XML follows the basic syntax rules: proper nesting, matching tags, quoted attributes, and a single root element. Valid XML goes further and conforms to a specific DTD or XML Schema that defines which elements and attributes are allowed and in what structure. All valid XML is well-formed, but not all well-formed XML is valid.

CDATA sections (<![CDATA[ ... ]]>) allow you to include text that would otherwise need escaping, such as code containing < and & characters. The XML parser treats everything inside a CDATA section as plain text, not markup. They are commonly used to embed scripts or code snippets within XML documents.

XML namespaces prevent element name conflicts when combining XML documents from different sources. They use URIs as unique identifiers, declared with xmlns attributes. For example, xmlns:xsl="http://www.w3.org/1999/XSL/Transform" declares the xsl prefix. Namespaces are essential in technologies like XSLT, SOAP, and SVG.