XML Formatter & Validator

1. Paste or type your XML into the input area, or click an example to get started.
2. Choose "Format" to beautify with indentation or "Minify" to strip whitespace.
3. If the XML has syntax errors, a descriptive error message is shown instead of output.
4. Adjust the indentation size using the dropdown when in Format mode.
5. Click "Copy" to copy the result to your clipboard.

What is XML Formatting?

XML (Extensible Markup Language) formatting is the process of applying consistent indentation, line breaks, and whitespace to an XML document so that its hierarchical structure is clearly visible. XML is widely used for configuration files, data interchange between systems, SOAP web services, RSS and Atom feeds, and SVG graphics. Unformatted or minified XML can be very difficult to read, especially when documents contain deeply nested elements or long attribute lists. This tool parses your XML, checks for well-formedness errors, and outputs a cleanly indented version.

How XML Formatting Works

The formatter parses your input using a DOM parser, which builds a tree representation of the XML document. If the document is not well-formed (missing closing tags, improperly nested elements, unquoted attributes), the parser reports the specific error. Once parsed successfully, the tool walks the tree and serializes each node with proper indentation based on its depth in the hierarchy. Opening and closing tags are aligned vertically, and child elements are indented one level deeper than their parent. Self-closing tags, CDATA sections, and comments are preserved and formatted in place. When minifying, all non-essential whitespace between tags is stripped to produce the most compact output possible.

Common Use Cases

• Debugging SOAP API responses and XML-based web service payloads
• Reading and editing Maven POM files, Spring configurations, and other XML config files
• Inspecting and cleaning up SVG file markup
• Formatting RSS and Atom feed content for review
• Minifying XML for production deployment to reduce file size
• Comparing XML documents side by side after formatting

Well-Formed XML vs Valid XML

It is important to understand the distinction between well-formed and valid XML. A well-formed XML document follows the basic syntax rules of XML: every opening tag has a matching closing tag (or is self-closing), tags are properly nested, attribute values are quoted, and there is exactly one root element. This is what the formatter checks. A valid XML document goes further by conforming to a schema definition, such as an XML Schema Definition (XSD) or Document Type Definition (DTD), which specifies which elements and attributes are allowed and how they must be structured.

Most formatting tools, including this one, check for well-formedness only. Schema validation is a separate step that requires a schema file and is typically performed by application-level XML processors. Common well-formedness errors include mismatched tag names, missing closing tags, unescaped ampersands in text content, and attributes without quotes. If you see an error from this tool, it usually means one of these basic rules has been violated.

Need to escape special characters before embedding them in XML? Use our XML Escape Tool. For formatting other structured data, try the JSON Formatter or the SQL Formatter. You can also encode HTML-specific entities with the HTML Entity Encoder.