Format and Validate Your XML Instantly

Paste your messy XML code to automatically format and indent it for perfect readability. Our tool also validates your XML in real-time, checking for syntax errors, missing tags, and compliance with W3C standards.

XML Input

Indent:spaces

Formatted XML

Output will appear here...

About XML Formatter & Validator

Format XML for readability with proper indentation, or minify it for production use. The tool also validates XML structure and reports syntax errors. Formatted XML is easier to read and debug, while minified XML reduces file size for faster transmission.

How It Works

This XML formatter and validator parses your XML code and restructures it with consistent indentation and line breaks. It simultaneously checks for well-formedness, ensuring your XML follows W3C standards.

The formatting process:

Parse XML: Your input is parsed into a DOM tree structure, validating syntax as it goes.
Validate structure: The parser checks for proper tag matching, attribute syntax, and entity usage.
Reformat output: The tree is serialized back to text with consistent indentation (2 or 4 spaces, or tabs).
Report errors: Any syntax errors are reported with line and column numbers for easy fixing.

The validator catches common errors like unclosed tags, mismatched quotes, invalid characters, and malformed entity references. Error messages point to the exact location of problems.

When You'd Actually Use This

Reading minified XML from logs

Application logs often contain single-line XML for brevity. Format it to actually read and understand what's in there.

Fixing XML syntax errors

Getting a parse error but can't spot the problem? The validator highlights exactly where the syntax breaks.

Preparing XML for code review

Before submitting XML changes for review, format them consistently. Reviewers can focus on content, not wrestling with indentation.

Cleaning up hand-edited XML

After manually editing complex XML, run it through the formatter to fix any accidental indentation inconsistencies.

Debugging API responses

XML API responses are often compact. Format them in your browser to inspect the structure and values during debugging.

Validating XML before processing

Before feeding XML to your application, validate it first. Catch errors early instead of dealing with cryptic runtime failures.

What to Know Before Using

Well-formed vs valid XML

Well-formed means correct syntax (matching tags, proper nesting). Valid means it also conforms to a schema (XSD or DTD). This tool checks well-formedness.

Comments and processing instructions are preserved

XML comments () and processing instructions (<?target?>) are kept during formatting. They're part of the document structure.

CDATA sections maintain content exactly

Content inside <![CDATA[...]]> is not formatted or escaped. It's preserved byte-for-byte as written.

Attribute order may change

XML attributes are unordered. The formatter may output them in a different order—this doesn't affect the document's meaning.

Whitespace in text content is preserved

Significant whitespace inside elements (like in formatted text or code) is preserved. Only ignorable whitespace between elements is normalized.

Common Questions

What makes XML 'well-formed'?

Well-formed XML has: one root element, properly nested tags, quoted attributes, escaped special characters, and valid character encoding.

How is this different from XML validation against a schema?

This checks syntax only (well-formedness). Schema validation checks if elements and attributes match a predefined structure and data types.

Can this fix my broken XML automatically?

No, it only formats valid XML. Broken XML needs manual fixes. The error messages help you locate and understand what to fix.

Does formatting change the XML meaning?

No. Formatting only adds/removes whitespace between elements. The parsed document tree is identical before and after formatting.

What indentation style should I use?

2 spaces is common for config files. 4 spaces is traditional for documents. Tabs are fine for internal tools. Consistency matters most.

Can I format partial XML fragments?

Most formatters need a complete document with one root. Wrap fragments in a temporary root element, format, then extract the content.

Why does my formatted XML look different from the original?

Formatting normalizes whitespace. Line breaks and indentation between elements are adjusted for consistency. Text content inside elements stays the same.

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