Format and Pretty-Print XML Online

Pretty-Printing XML

Pretty-printing transforms compact or single-line XML into a well-structured, indented document that is easy for humans to read and edit. The formatter parses the XML into a DOM tree and then serializes it back with consistent indentation and line breaks.

How Pretty-Printing Works

Given a compact XML string:

<catalog><book id="1"><title>XML Developer's Guide</title><price>44.95</price></book></catalog>

The formatter produces:

<catalog>
  <book id="1">
    <title>XML Developer's Guide</title>
    <price>44.95</price>
  </book>
</catalog>

Each nested element is indented by a consistent amount (commonly 2 or 4 spaces), and each opening/closing tag pair gets its own line when the element contains children.

Indentation Options

Most formatters offer several indentation styles:

• 2 spaces — compact, popular in web development and JavaScript ecosystems
• 4 spaces — more visually distinct hierarchy, common in Java and enterprise XML
• Tab characters — preferred by some teams for accessibility and configurability
• 1 space — rarely used, but minimizes file size while maintaining readability

Attribute Formatting

When elements have many attributes, formatters can optionally place each attribute on its own line:

<element
  attr1="value1"
  attr2="value2"
  attr3="value3" />

This is especially useful for configuration files where elements carry many attributes.

Preserving Content

A good formatter preserves text content exactly as it appears. Mixed-content elements (elements containing both text and child elements) require careful handling to avoid introducing unwanted whitespace into the text.

Self-Closing Tags

Empty elements like <br/> or <item/> can be formatted as self-closing tags or as explicit open/close pairs (<item></item>). Most formatters default to self-closing for brevity.