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XML Formatter

Name: XML Formatter - WebUtil
Author: WebUtil

Format, validate, and beautify XML data with syntax highlighting.

XML Input

Formatted Output

What Is XML Formatting?

XML formatting (also called XML beautification or XML pretty-print) is the process of restructuring raw XML data with proper indentation, line breaks, and spacing to make the document structure human-readable. A formatted XML document uses consistent indentation to show each element's nesting level, making it dramatically easier to spot errors, understand relationships, and edit the data. Our free XML formatter online runs entirely in your browser for instant, private formatting.

XML vs JSON vs YAML

XML

Best for documents with mixed content (text + elements), complex schemas (XSD), and enterprise systems like SOAP web services and configuration files. Supports attributes, namespaces, and comments out of the box.

JSON

Best for REST APIs, web applications, and lightweight data exchange. JSON has a simpler syntax and is natively supported in JavaScript, making it faster to parse in browser environments.

YAML

Best for configuration files (Docker Compose, CI/CD pipelines, Ansible) where human readability is the top priority. YAML uses indentation-based structure and supports comments and multi-line strings.

Common XML Use Cases

Configuration Files — Application configs in XML (e.g., Maven POM, Ant build files, web.xml).
Web Services (SOAP) — SOAP APIs exchange structured XML messages between systems.
Data Exchange — XML is widely used in B2B integrations, RSS/Atom feeds, and OpenStreetMap data.
Document Storage — Office documents (DOCX, XLSX) and SVG graphics are XML-based under the hood.

How to Use This XML Formatter

To format XML data, paste your raw XML string into the input textarea and click Format XML. The tool will parse the document and output a beautifully indented version. Each nesting level adds two spaces of indentation so the element hierarchy is clearly visible. If the XML contains syntax errors, an error message explains what went wrong. Use the Copy button to copy the formatted result to your clipboard.

XML (eXtensible Markup Language), standardized by the W3C, is a foundational markup language for encoding structured documents and data. While JSON dominates public web APIs, XML remains the backbone of enterprise software, SOAP web services, RSS and Atom feeds, Android layout resources, SVG graphics, Office Open XML documents (DOCX, XLSX), and financial exchange protocols (FIX, SWIFT). In production environments, XML payloads transmitted over the wire are frequently minified into dense single-line strings without whitespace to reduce bandwidth. Inspecting or debugging these files requires reformatting into a hierarchical tree with proper indentation, tag alignment, and attribute wrapping. An XML formatter parses document structure, validates opening and closing tags, checks attribute quote consistency, and highlights syntax errors such as mismatched tags or unclosed elements. WebUtil's XML Formatter & Validator beautifies XML documents, strips unnecessary whitespace, and checks well-formedness entirely in your browser with zero server uploads.

How to Do This in Code

function formatXml(xml) {
  const xsltDoc = new DOMParser().parseFromString(
    '<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">' +
    '<xsl:output indent="yes" method="xml"/>' +
    '<xsl:template match="/"><xsl:copy-of select="."/></xsl:template></xsl:stylesheet>', 'text/xml');
  const result = new XSLTProcessor();
  result.importStylesheet(xsltDoc);
  return new XMLSerializer().serializeToString(result.transformToDocument(xmlDoc));
}

import xml.dom.minidom
formatted = xml.dom.minidom.parseString(xml_str).toprettyxml(indent='  ')

xmllint --format input.xml
# or:
xq . input.xml | jq .

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Related Guides & Tutorials

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XML Formatter Guide: How to Format, Validate, and Beautify XML

Master XML formatting with best practices for indentation, validation, and comparing XML vs JSON.

XML Formatter FAQ

What is the difference between well-formed XML and valid XML?

Well-formed XML obeys basic XML syntax rules (matching tags, unique attributes, proper root element). Valid XML additionally conforms to a specific schema definition (DTD or XSD).

How does the XML formatter handle CDATA sections and comments?

WebUtil preserves CDATA sections (<![CDATA[ ... ]]>) and XML comments intact without altering their internal content or line breaks.

Can this tool format SOAP API payloads and RSS XML feeds?

Yes. WebUtil handles complex enterprise SOAP envelopes, XML namespaces (xmlns), and RSS/Atom feeds with clean hierarchical indentation.

What causes the common 'mismatched tag' XML error?

XML is strictly case-sensitive. A mismatch error occurs when an opening tag does not match its closing tag (e.g. <Item> ... </item>) or when nested tags overlap improperly.

Is my proprietary XML data processed privately?

Yes. All XML parsing and beautification runs locally in your browser. No files, corporate configurations, or data are transmitted over the internet.