XML Formatter & Validator - Online Tool

What an XML Formatter Should Do

XML is where Spring contexts, web.xml descriptors, Maven POMs, SOAP envelopes and RSS feeds live. Unlike YAML, whitespace between elements carries no meaning — which is exactly why real-world XML arrives as one enormous line, or indented three different ways by three different tools.

This formatter parses the document before it writes anything. It recovers the element tree, then re-emits it at one consistent indent width. A minified SOAP response and a hand-indented build file come out looking the same.

<beans><bean id="greeter"
class="com.example.Greeter">
<constructor-arg ref="dataSource"   />
</bean></beans>

<beans>
  <bean id="greeter" class="com.example.Greeter">
    <constructor-arg ref="dataSource"/>
  </bean>
</beans>

It Validates Before It Writes

Because the document is parsed first, a document that is not well-formed is rejected with the line number rather than re-indented into something that looks fine and still will not load:

• A mismatched closing tag — <bean>…</bena>
• An unclosed element, reported at the point the document ends
• A bare & that should have been & — the most common way a query string breaks a config file
• An unquoted attribute value
• More than one root element
• An unterminated comment or CDATA section

It checks that the document is well-formed, which is not the same as valid: it will not fetch your XSD or DTD and tell you that maximumPoolSize was supposed to be an integer. Comments, CDATA sections, processing instructions and the XML declaration are all preserved.

You Get the Shape of the Document

Alongside the formatted output the tool reports the document element, how many elements and attributes it holds, how many distinct namespaces are declared, and how deep the nesting goes. On a SOAP response or a 4,000-line POM that is usually the fastest way to tell whether you were handed what you expected — a namespace count of three when you expected one is a routing problem, not a formatting problem.

Minify Stays in Your Browser

The Minify button never sends anything anywhere. It drops the whitespace between elements and collapses runs of whitespace inside text to a single space, while copying CDATA sections, comments and attribute values through byte for byte — because whitespace inside a CDATA block is part of your value, not part of the layout. It refuses to run on a document that will not parse, so it cannot silently mangle broken XML.

Where XML Bites

Formatting Is Idempotent

Running the formatter on its own output produces exactly the same text, so repeated use never drifts and formatted XML committed to version control will not produce a spurious diff the next time somebody formats it.

Privacy and Limits

Formatting and validation run on our servers: your document is sent over HTTPS, processed, and returned. It is never shared with third parties or used for advertising. Even so, treat it as an upload — datasource passwords, keystore entries, API keys and certificates do not belong in any online tool, this one included. Redact them first, or format a representative sample. Input is capped at 2 MB. Minify is the exception: it never leaves your browser.

Working with other formats too? The YAML formatter covers the config format that replaced half of these files, the JSON formatter handles API payloads, and the Java formatter takes the same conservative approach to the code that reads them.