XML Formatter & Validator

Format, validate, and beautify XML instantly. Pretty print with configurable indentation and syntax highlighting for tags, attributes, values, comments, and CDATA sections. Minify XML for production use, check well-formedness with detailed error reporting, and view document statistics. Free, runs entirely in your browser -- no data ever leaves your machine.

Input Paste or type XML
Output
Formatted output will appear here...

Features

Pretty Print

Format any XML with configurable indentation -- choose 2 spaces, 4 spaces, or tabs. The output is clean, readable, and ready to copy or download as an .xml file.

Validation

Validate XML well-formedness instantly using the browser's built-in DOMParser. Get detailed error messages when your XML has mismatched tags, improper nesting, or invalid syntax.

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Syntax Highlighting

Color-coded output distinguishes tags, attributes, values, comments, and CDATA sections at a glance. Line numbers make it easy to reference specific parts of your XML structure.

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Minification

Compress XML by removing whitespace, line breaks, and comments. See exactly how many characters were saved. Ideal for network transfer and storage optimization.

About XML Formatting

XML (eXtensible Markup Language) remains one of the most important data formats in enterprise software, web services, and configuration management. While JSON has become the dominant format for web APIs, XML continues to be essential for SOAP web services, Maven build files, Android layouts, SVG graphics, RSS/Atom feeds, XSLT transformations, and many legacy systems. A reliable XML formatter is an indispensable tool for any developer working with these technologies.

Why Format XML?

Formatting XML -- also called pretty printing or beautifying -- adds proper indentation and line breaks to make the document structure visible at a glance. When you are debugging a SOAP response, reviewing a Maven POM file, or inspecting an SVG graphic, formatted XML lets you quickly identify nested elements, attributes, namespaces, and structural patterns. Minified XML removes all unnecessary whitespace to reduce file size for production use, network transfer, and storage.

How This Tool Works

Paste your XML into the input pane and click Format to pretty print it with syntax highlighting and line numbers. Click Minify to compress it by removing whitespace and comments. Click Validate to check if the document is well-formed. The tool uses the browser's built-in DOMParser for validation, providing accurate error messages when parsing fails. Everything runs entirely in your browser -- no data is ever sent to a server.

Common Use Cases

Frequently Asked Questions

What is XML?
XML (eXtensible Markup Language) is a markup language designed to store and transport data in a structured, human-readable, and machine-readable format. Unlike HTML, which has predefined tags for displaying content, XML allows you to define your own tags to describe your data. XML is a W3C standard and is widely used in web services (SOAP), configuration files (Maven POM, Spring XML, Android manifests), document formats (XHTML, SVG, RSS/Atom), data interchange between enterprise systems, and office document formats (OOXML, ODF). XML documents consist of elements (tags), attributes, text content, comments, processing instructions, and CDATA sections.
How do I format XML?
To format XML using this tool, paste your raw, minified, or unformatted XML into the input textarea on the left side. Select your preferred indentation level (2 spaces, 4 spaces, or tabs) from the dropdown menu, then click the "Format" button. The tool will parse your XML, validate its well-formedness, and display a beautifully formatted version in the output pane with syntax highlighting and line numbers. Tags, attributes, values, comments, and CDATA sections are each highlighted in distinct colors. You can then copy the formatted output to your clipboard or download it as an .xml file.
What makes XML well-formed?
A well-formed XML document must satisfy several rules: it must have exactly one root element that contains all other elements, every opening tag must have a corresponding closing tag (or be self-closing like <br/>), tags must be properly nested without overlapping (e.g., <a><b></b></a> is valid but <a><b></a></b> is not), all attribute values must be enclosed in quotes (single or double), element and attribute names are case-sensitive (<Name> and <name> are different), and special characters must be escaped using entities (&lt; for <, &gt; for >, &amp; for &). Documents that follow all these rules can be parsed by any XML parser.
What is the difference between XML and HTML?
While both XML and HTML are markup languages derived from SGML, they serve fundamentally different purposes. HTML is designed to display data in web browsers with a fixed set of predefined tags (h1, p, div, span), while XML is designed to carry and describe data with user-defined tags. XML is strictly parsed -- every tag must be properly closed and nested, attribute values must be quoted, and the parser will reject any malformed document. HTML browsers, by contrast, are lenient and will render even poorly formed markup. XML is case-sensitive (so <Name> and <name> are different elements), while HTML is case-insensitive. XHTML is a variant that applies XML's strict rules to HTML, requiring well-formed documents.
What is CDATA in XML?
CDATA (Character Data) sections are a way to include blocks of text in XML that should not be parsed as markup. Content inside a <![CDATA[ ... ]]> block is treated as literal text, meaning characters like <, >, and & do not need to be escaped. CDATA sections are commonly used to embed code snippets (JavaScript, SQL, HTML), include text with many special characters, store raw data that should not be processed by the XML parser, and embed HTML fragments inside XML documents. The only sequence that cannot appear inside a CDATA section is the closing delimiter ]]>.
What is XML minification?
XML minification removes all unnecessary whitespace characters from an XML document -- including spaces, tabs, line breaks, and indentation -- as well as comments, while preserving the data and structure exactly. The resulting minified XML is a compact single line that is functionally identical to the formatted version but takes up significantly less space. Minification is commonly used when sending XML data over a network (SOAP requests, webhook payloads) to reduce bandwidth usage, when storing XML in databases or caches to save storage space, and in configuration files where space is limited. Our Minify button instantly compresses your XML and shows you exactly how many characters were saved.
How do I validate XML?
To validate XML, paste your XML into the input area and click the "Validate" button. The tool uses the browser's built-in DOMParser, which checks whether the document is well-formed according to the XML specification. If the XML is valid, you will see a green success message confirming the document is well-formed. If it is invalid, you will get a detailed error message indicating what went wrong -- such as mismatched tags, missing closing elements, unescaped special characters, or invalid attribute syntax. Note that this tool checks well-formedness (syntactic correctness), not validity against a DTD or XML Schema, which would require schema definitions.
What are XML namespaces?
XML namespaces provide a mechanism to avoid element and attribute name conflicts when combining XML documents from different vocabularies. A namespace is declared using the xmlns attribute and associates a prefix with a unique URI (which serves as an identifier, not necessarily a web address). For example, xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" allows you to use the soap: prefix to distinguish SOAP elements from other elements with the same local name. Namespaces are essential in SOAP web services, XSLT stylesheets, XSD schemas, SVG embedded in HTML, and any scenario where multiple XML vocabularies coexist in the same document. A default namespace can be declared without a prefix using xmlns="...".

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