What is an XML Formatter?
An XML formatter (also called XML beautifier or XML indenter) takes raw or minified XML text and adds consistent indentation and line breaks to make it human-readable. It also validates the XML structure — reporting errors like unclosed tags, mismatched nesting, or illegal characters. This is essential when working with API responses, configuration files, SOAP envelopes, Android layouts, or any XML-based format.
How to Use the XML Formatter
Paste your XML into the input panel on the left. Click "Format XML" to beautify with your chosen indentation (2 spaces, 4 spaces, or tab). The formatted result appears on the right. If the XML is invalid, a red error bar shows the specific issue. Click "Minify" to collapse to a single line, "Copy" to copy the output, or "Clear" to reset both panels.
How the XML Formatter Works
The formatter uses the browser's built-in DOMParser API (part of the W3C DOM standard) to parse the XML. If parsing succeeds, it serializes the DOM tree back to a string with proper indentation using a recursive tree traversal. If the parser reports an error, it extracts the error location and shows it to the user. No external libraries are needed — the browser's XML parser handles it all.
Benefits of Formatting XML
- Makes deeply nested XML readable at a glance
- Quickly validates whether XML is well-formed before using it in code
- Minification reduces payload size for network requests
- 100% client-side — no data leaves your browser
- Works with any XML: SOAP, RSS, SVG, Android layouts, Maven POM, config files
Frequently Asked Questions
What is XML and how is it different from HTML?
XML stores and transports structured data using user-defined tags. HTML describes web page presentation using predefined tags. XML is case-sensitive and requires all tags to be closed. HTML is more forgiving. XML is the foundation of DOCX, XLSX, SVG, RSS, and SOAP.
What is a well-formed XML document?
A well-formed XML document has: one root element, all tags closed, proper nesting (no overlapping), quoted attribute values, and valid characters. Our formatter validates all these rules and shows specific error messages.
What is an XML namespace?
Namespaces prevent naming conflicts when combining XML from different vocabularies. Declared with xmlns:prefix="uri". Common in SOAP, XHTML, and SVG. The formatter preserves all namespace declarations.
What is the difference between XML and JSON?
JSON is compact and native to JavaScript. XML supports attributes, CDATA, comments, and processing instructions — better for documents. JSON is standard for REST APIs. XML for SOAP, config files, and document formats. Use our JSON Formatter for JSON.
What does XML minification do?
Removes all whitespace, newlines, and indentation between tags — reducing file size for transmission. Structure and data remain identical.
Is my XML data private when using this formatter?
Yes. The formatter runs entirely in your browser using the DOM parser. No data is sent to any server. Safe for sensitive configuration files and API responses.
What is a CDATA section in XML?
A CDATA section (<![CDATA[ ... ]]>) wraps content that should not be parsed as XML markup. Allows characters like <, >, and & to appear literally. Common for embedding HTML or scripts inside XML.
What indentation settings should I use for XML?
2 spaces (W3C standard), 4 spaces (Java/Maven convention), or tab (older enterprise environments). All are valid — choose based on your team's style guide.