Format, Validate & Minify XML Instantly
Free online XML formatter, validator, and minifier that runs entirely in your browser — no data ever leaves your device.
About the XML Formatter
This tool parses your XML in the browser using the same DOMParser engine built into every modern browser, then re-serializes it with clean, consistent indentation. Attributes, text, comments, CDATA sections, and processing instructions are all preserved, so the structure of your document never changes — only its formatting does.
Features:
- Format XML with 2-space, 4-space, or tab indentation
- Minify XML by stripping all non-essential whitespace
- Validate well-formedness with clear, human-readable error messages
- Preserves comments, CDATA sections, attributes, and the XML declaration
How to Format XML
- Paste or type your XML into the input box
- Choose your preferred indentation size
- Click Format to pretty-print, or Minify to compress
- Copy the result or download it as an .xml file
Frequently Asked Questions
Is my XML data uploaded to a server?
No. Parsing and formatting happen entirely in your browser using the built-in DOMParser API — your XML never leaves your device.
What's the difference between Format and Minify?
Format adds indentation and line breaks so nested tags are easy to read. Minify removes all non-essential whitespace to produce the smallest possible output, useful for storage or transmission.
Does this tool support XML namespaces?
Yes. Namespace prefixes (like ns:tag) and their attributes are preserved exactly as written, since the browser's parser understands them natively.
Why does my XML pass in the browser but fail validation here?
This tool checks that your XML is well-formed — that every tag is properly closed and nested — which is what browsers require to parse it at all. It does not validate against a DTD or XML Schema, so XML that is well-formed but doesn't match a particular schema will still show as valid here.
What happens to the XML declaration when I format or minify?
If your input starts with a declaration like <?xml version="1.0"?>, it's detected and re-added to the output automatically, since browsers strip it from the parsed document.
Are comments and CDATA sections preserved when formatting?
Yes, comments (<!-- ... -->) and CDATA sections (<![CDATA[ ... ]]>) are kept exactly as they appear in your input. One limitation: DOCTYPE internal subsets are not preserved.
Privacy
Your XML is processed entirely in your browser. Nothing is uploaded, stored, or sent to any server.