XML Formatter

Understanding the Basics

XML documents from SOAP services, database exports, and configuration systems are frequently delivered as dense single-line strings or with inconsistent indentation that makes them impossible to read at a glance. XML formatting applies consistent indentation (typically two or four spaces per nesting level) and line breaks after every element opening and closing tag, transforming a wall of markup into a visually navigable tree structure. This is especially critical when reviewing SOAP request/response pairs, Spring Boot XML application contexts, Maven POM files, or Android layout XMLs where attribute ordering and element hierarchy carry important structural meaning. The reverse operation — XML minification — strips all non-functional whitespace to produce compact output suitable for transmission over networks or storage in size-sensitive systems. Unlike JSON minification, XML minification must be careful not to strip whitespace inside elements where it is significant (mixed content, pre-formatted text). Our formatter uses the fast-xml-parser library to parse and re-serialize XML with configurable indentation, preserving CDATA sections, processing instructions, and XML declarations correctly.

How to Use the Tool

1. Paste your XML content into the input editor.
2. Choose "Prettify" to format with indentation or "Minify" to strip whitespace.
3. Set the indentation size (2 or 4 spaces) from the settings panel.
4. The formatted or minified XML appears in the output editor immediately.
5. Copy or download the result for use in your configuration files, API testing, or documentation.

Key Features & Specifications

• Prettify mode: adds consistent indentation and line breaks for human readability
• Minify mode: removes all non-significant whitespace for compact transmission
• Preserves CDATA sections, comments, and processing instructions during reformatting
• Preserves XML declaration (<?xml version="1.0"?>) at the top of the output
• Configurable indentation: 2-space, 4-space, or tab character

Frequently Asked Questions (FAQ)

Q:Will formatting break mixed content (text mixed with child elements)?

Formatting adds whitespace around elements, which technically changes mixed-content documents. For elements where whitespace is significant (like <pre> equivalents), the formatter respects xml:space="preserve" declarations to avoid altering text nodes.

Q:My CDATA section content disappeared after formatting — why?

This would be a bug. Our formatter is configured to preserve CDATA sections intact, passing them through verbatim during reformatting. If you encounter this, please try wrapping the CDATA content in your own test and check if the issue is in the input rather than the formatter.

Q:Can I format XML with custom namespaces (xmlns:)?

Yes. Namespace declarations (xmlns: prefixed attributes) are treated as regular attributes during formatting and are preserved on the element where they were declared. The formatter does not restructure namespace bindings.