XML Formatter, Minifier & Validator

Paste any XML document — an RSS or Atom feed, a sitemap.xml, a SOAP envelope, a Spring config, an OpenAPI document, a Web App Manifest — and get it back pretty-printed, minified, or validated for well-formedness. Errors are surfaced at the exact line and column of the bad byte. Everything runs in this tab; nothing is uploaded.

Mode
Options

Pretty-print

Minify

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Element tree (read-only)

A condensed view of the parsed element tree with element names, attribute counts, and a one-line preview of each text child. Updates live as you type.

    How the formatter works
    • Pretty-print re-emits your XML with a chosen indent (2 spaces, 4 spaces, or a tab). Text-only children stay on the same line as their parent tag; block-level content gets its own line per element. Self-closing tags stay self-closing.
    • Minify drops every run of whitespace between tags and (by default) collapses internal whitespace inside text to a single space. Use Preserve text content when you want the bytes inside elements (the actual data) untouched, but the markup around them compacted.
    • Validate only clears the output box and just reports whether the document is well-formed. Useful as a CI-style quick check.
    • Errors are reported with the exact line and column of the offending byte: unclosed tags, unterminated comments, bad entity references, missing quotes, mismatched end tags, top-level text, duplicate root elements, and so on.
    • The formatter handles XML declarations (<?xml … ?>), DOCTYPE declarations, comments, CDATA sections, and processing instructions like <?xml-stylesheet … ?>. The five predefined entities (&lt; &gt; &amp; &apos; &quot;) and decimal / hex character references are decoded on read and preserved verbatim on write.
    • Nothing leaves the browser. The whole tool runs on a 20 KB script and your document never touches the network.

    About this tool

    XML Formatter pretty-prints and validates XML in your browser. It detects syntax errors with line and column numbers, supports a configurable indent, and offers an option to sort attributes alphabetically for stable diffs. The validator follows the XML 1.0 spec, including the rule for well-formedness (matching start and end tags, properly escaped entities, a single root element). It does not validate against a schema (XSD, DTD) — that requires a schema-aware tool.

    When to use it

    • Pretty-printing a minified XML payload from a network request
    • Validating a hand-edited config file (Maven pom, Android manifest, sitemap) before saving
    • Sorting attributes alphabetically to make a config diff easier to read
    • Recovering a malformed snippet by re-indenting it after a manual edit

    When not to use it

    • You need XSD or DTD validation — this checks well-formedness, not schema conformance. Use xmllint or a schema-aware validator for that
    • You need to edit XML interactively — use a real XML editor (oXygen, VS Code with the XML extension)
    • You need to transform XML with XSLT or XPath — this formats, it does not transform

    Frequently asked questions

    Does it validate against a schema?

    No. The formatter checks well-formedness — that the document parses as XML 1.0. Schema validation (XSD, DTD, RelaxNG) is a separate step and requires a schema-aware tool.

    Does it preserve CDATA sections?

    Yes. CDATA is preserved as-is in the formatted output. The formatter does not collapse CDATA into escaped text.

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