Key takeaways
- 01Pretty-print XML with 2 spaces, 4 spaces, or tab indentation — or minify to remove all whitespace.
- 02Validation uses the browser's native DOMParser, giving the same errors your in-browser XML library would produce.
- 03Works on large multi-megabyte XML files entirely in-browser — no server round-trip.
- 04XML content never leaves your device.
When You Need to Format or Validate XML
XML is still everywhere — Maven POM files, SOAP API responses, RSS and Atom feeds, SVG graphics, Android layout resources, Microsoft Office Open XML, and legacy enterprise integrations. The problem is that XML in the wild often arrives as a single unbroken line from an API response or a generated file. Reading it or debugging it without formatting is nearly impossible.
Beyond readability, well-formedness matters. A missing closing tag or an unescaped ampersand makes an XML document invalid. The browser's built-in DOMParser surfaces those errors with line and column numbers so you can fix them immediately, without spinning up a local parser or pasting into an IDE.
How to Format or Validate XML
- 01
Paste your XML
Paste any XML document — a config file, API response, RSS feed, SVG, or SOAP envelope. Files of several megabytes are handled without issue.
- 02
Choose Format or Minify
Format adds line breaks and consistent indentation (2 spaces, 4 spaces, or tabs). Minify strips all inter-tag whitespace, producing the most compact version for transmission.
- 03
Validate if needed
Click Validate to run the document through the browser's DOMParser. If the XML is well-formed, you'll get a confirmation. If not, the error message includes the exact line and column.
- 04
Copy the result
Click Copy to grab the formatted or minified XML. Paste it into a file, a code review, or a test fixture.
Common Reasons Developers Use an XML Formatter
- 01A SOAP API response arrives as one line — format it to read the structure.
- 02A Maven pom.xml has mixed tabs and spaces — normalize before committing.
- 03An RSS or Atom feed fails to parse — validate to find the first malformed tag.
- 04SVG markup exported from Illustrator needs cleanup before embedding in HTML.
- 05A Word or Excel file's extracted XML needs to be readable for debugging.
- 06Minify a config XML for embedding in a mobile app bundle to reduce size.
No Uploads, No Server
Formatting and minification are pure JavaScript string operations running in your browser tab. Validation uses the browser's native DOMParser — the same engine your browser uses to render web pages. No XML content is sent to any server.
XML namespaces are fully supported. Elements like <ns:element xmlns:ns="http://example.com"> pass through formatting and minification unchanged. The formatter does not rewrite namespace prefixes or restructure the document.
XML Formatter FAQ
Does it support XML namespaces?
Yes. Namespace declarations and prefixed elements are preserved unchanged through formatting and minification.
Will it validate against an XSD schema?
No — only well-formedness is checked (balanced tags, quoted attributes, escaped characters). Schema validation requires a separate tool that loads your XSD.
Can it handle large XML files?
Yes. Formatting runs as a pure JavaScript string operation, so multi-megabyte files process quickly. Your browser's available memory is the only practical limit.
Is the XML uploaded to any server?
No. All operations run in your browser using native JavaScript and the DOMParser.
What does minify actually do?
Minify removes whitespace between tags (line breaks, spaces used for indentation), producing the smallest possible valid XML. The content of text nodes is preserved.