XML Formatter & Validator

Quick answer: XML Formatter & Validator is a free online tool: validate and pretty-print XML in one step — paste messy or minified XML to get clean indentation and clear error messages. No account or install needed — it runs entirely in your browser, free.

Validate and pretty-print XML in one step — paste messy or minified XML to get clean indentation and clear error messages.

What is the XML Formatter & Validator?

XML is strict: one unclosed tag, one mismatched case, one stray ampersand, and the entire document is invalid — which is why APIs, config files, and data feeds so often arrive as either minified walls of text or subtly broken payloads. This tool does two jobs at once: it validates your XML with a real parser and, when the document is well-formed, pretty-prints it with consistent indentation so the element hierarchy is obvious.

If the XML is broken, you don’t get a mangled reformat — you get a precise error message pointing at the problem (unexpected closing tag, unclosed element, invalid character) so you can fix it at the source. Attributes, namespaces, CDATA sections, comments, and processing instructions are all preserved through formatting; only whitespace between elements is normalized. Developers use it to inspect API responses, debug SOAP payloads and RSS feeds, tidy SVG files, and review Android layouts or Maven POMs. Choose your indent width to match your project’s style. Everything runs locally — your payloads never leave the browser. Invalid or valid, minified or messy — paste it and see.

How to use the XML Formatter & Validator

  1. Paste your XML — minified, messy, or suspect — into the input box.
  2. Set the indent width (2 spaces is the common default).
  3. Click Format XML to validate and pretty-print in one step.
  4. If errors are reported, fix the flagged issue in your source and re-paste.
  5. Copy the formatted XML or download it as a .xml file.

XML Formatter & Validator use cases

API debugging

Pretty-print a minified XML response to find the field or namespace causing failures. Hierarchies that were invisible on one line become navigable structure you can actually trace. Structure reveals what flat text hides.

Config review

Make AndroidManifest, POM, or web.config files readable before editing them by hand. A clean indent reveals nesting mistakes before they become painful runtime errors. Prevention always beats debugging in production.

RSS/Atom feeds

Validate a feed that’s failing in readers and pinpoint the malformed entry. Feed validators just say ‘invalid’; this tool shows you exactly which tag broke and where. Precision saves hours of guessing.

SVG cleanup

Re-indent exported SVG markup so it’s editable without a headache. Design tools export single-line SVG that no human should ever have to read raw. Editable markup is maintainable markup.

SOAP services

Inspect verbose SOAP envelopes layer by layer instead of scrolling one endless line. Namespaces and nested bodies become easy to trace from the outer envelope inward. Layers become manageable with indentation.

Tips

  • An XML document must have exactly one root element — multiple roots is the most common validation failure.
  • Special characters (&, <, >) inside text must be escaped as &amp;, &lt;, &gt; or wrapped in CDATA.
  • Formatting never alters your data — only whitespace between elements is normalized.
  • Match the indent width to your project so formatted files don’t create noisy diffs.

Frequently asked questions

What does well-formed XML mean?
It means the document obeys XML's syntax rules: exactly one root element, every tag properly closed and nested, attribute values quoted, and special characters escaped. Well-formed is the baseline — a document can be well-formed but still invalid against a schema.
What is the difference between formatting and validation?
Formatting rearranges whitespace for readability; validation checks the document against XML's rules. This tool validates first, because pretty-printing a broken document would just produce pretty broken output — instead you get an error describing the exact problem. Validation first, beauty second.
Why does it say my XML has multiple root elements?
XML allows only one top-level element. Fragments like pasted from logs or concatenated responses will fail validation — wrap them in a single container element and they will format cleanly. A single wrapper element fixes the problem instantly.
Are namespaces and CDATA preserved?
Yes. Namespace prefixes, CDATA sections, comments, processing instructions, and the XML declaration all survive formatting unchanged; only insignificant whitespace between elements is adjusted to your chosen indent. Your data passes through completely untouched. Guaranteed, every single time. Nothing is ever lost or altered.
Can it convert XML to JSON?
Not directly — that's a different transformation with semantic decisions (attributes vs. elements, repeated tags vs. arrays). Format and validate here, then use a dedicated XML-to-JSON converter for the conversion itself. Each tool here does its own job well.
Why did formatting change my whitespace inside text?
It doesn't touch text content: whitespace inside elements with actual text is preserved exactly as written. Only purely structural whitespace between elements is normalized to your chosen indent width. Your text content is sacred here; only the structure gets restyled.
Is my XML uploaded anywhere?
No. Parsing and formatting run entirely in your browser's JavaScript engine. Sensitive payloads, credentials in configs, and proprietary data stay on your machine at all times. That is why this tool is safe for production configs and private API payloads alike.