Free Online Tool

XML Formatter & Validator

Format, validate, and minify XML instantly in your browser

No data is sent to any server — everything runs client-side

XML Input

Paste your XML here

Input

Result

Formatted or minified output

Output

What Is XML Formatting?

XML formatting (pretty-printing) adds consistent indentation and line breaks to an XML document to make its hierarchical structure visually clear. Minified XML removes all non-essential whitespace to reduce file size for storage and transmission. Both operations preserve the document's data content and structure — only whitespace between tags changes.

Well-formatted XML is essential when reviewing configuration files (web.xml, pom.xml, .csproj), debugging SOAP responses, inspecting RSS/Atom feeds, or sharing XML structures with team members. Minified XML is used in production SOAP payloads, embedded XML in databases, and anywhere bandwidth or storage costs matter.

XML Validation: Common Errors

The validator checks whether your input is well-formed XML. Here are the most common errors developers encounter:

Mismatched tags

Every opening tag must have a matching closing tag with the same name. <item>...</items> is invalid.

Unescaped special characters

Characters like &, <, and > must be escaped as &amp;, &lt;, &gt; in text content and attribute values.

Missing root element

XML documents must have exactly one root element wrapping all content. Multiple top-level elements are not allowed.

Unquoted attribute values

Attribute values must be enclosed in either single or double quotes: <item id="42"> not <item id=42>.

Invalid element names

Element names cannot start with numbers or contain spaces. Names are case-sensitive, so <Item> and <item> are different elements.

When to Use This Tool

Debugging SOAP Responses

SOAP API responses are often returned as a single line of XML. Formatting makes it easy to see the Envelope, Header, Body structure and locate the data payload within nested elements.

Reviewing Config Files

Validate and format XML config files like web.xml, pom.xml, .csproj, or AndroidManifest.xml before committing. Catch mismatched tags and escaping issues early.

Inspecting RSS & Atom Feeds

RSS and Atom feeds are XML documents. Format them to see channel metadata, item structure, and enclosure details clearly before parsing in your application.

Minifying for Production

Remove whitespace from XML payloads before embedding in databases, sending over APIs, or including in SOAP requests to reduce bandwidth and storage costs.

XML Structure Quick Reference

ComponentExampleNotes
Element<name>value</name>The basic building block of XML
Attribute<item id="42">Key-value metadata on an element
Self-closing<br/>Element with no content
CDATA<![CDATA[raw text]]>Unescaped text block
Comment<!-- note -->Ignored by parsers
Declaration<?xml version="1.0"?>Optional, specifies version & encoding
Namespacexmlns:ns="http://..."Avoids name collisions between schemas

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