XML Formatter & Beautifier
Clean and indent raw XML instantly. Processed locally in your browser.
Why use an XML Formatter?
XML (eXtensible Markup Language) is heavily used in enterprise software, RSS feeds, and legacy APIs. Raw XML is often collapsed into an unreadable wall of text. Our XML Beautifier parses your document with the browser’s native XML parser and re-serializes the tree — so comments, CDATA sections, processing instructions, and mixed content are preserved exactly, never mangled the way a naive regex reformatter would. Choose your indent (2/4/tab) or Minify to strip whitespace and comments; invalid XML reports the exact line and column of the error.
Zero-Server Security Guarantee
Enterprise XML often contains highly sensitive configuration data. ZeroServer.tools never transmits your data. The formatting engine is written purely in JavaScript and runs locally on your machine, ensuring complete privacy.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Making a single-line SOAP or RSS payload readable enough to find the element you need.
- Normalising indentation on a config file before committing it.
- Checking the nesting of a document whose structure you are unsure about.
- Preparing an XML sample for documentation or a bug report.
- Confirming a document is well-formed before feeding it to a stricter parser.
How it works in practice
A worked example
A single-line document from a log needs indenting before anyone can review what it contains.
<?xml version="1.0"?><order id="AC-4471"><item sku="A-1" qty="2"/><note>a < b</note><empty></empty></order>
<?xml version="1.0"?> <order id="AC-4471"> <item sku="A-1" qty="2"/> <note>a < b</note> <empty/> </order>
The declaration stays on its own line, each child is indented one level, and the attributes are left exactly as written — order and spacing included, since an XML parser treats attribute order as insignificant but a diff does not. The escaped less-than sign is preserved as an entity rather than being decoded, which is the only correct choice: decoding it would produce a document that no longer parses. One element did change shape: the empty pair became a self-closing tag.
The edge case that catches people
That collapse is worth knowing about because it is a byte-level change to something a parser considers identical. An element with no content and a self-closing element are the same node in XML, so any conformant reader cannot tell them apart — but a signature over the document bytes can, and so can a system comparing files for equality. If a document is signed, or if it is being checked against a stored copy, format it to read it and send the original.
When not to use this tool
Formatting is not validation, and the two get confused because a formatter has to parse in order to indent. A document that indents cleanly is well-formed and may still be invalid against its schema — the elements can be in the wrong order, a required attribute can be missing, a value can be the wrong type, and none of that is visible here. And whitespace between elements is only insignificant if the schema says so: in a mixed-content element it is part of the text, so indenting can change the data.
Frequently Asked Questions
- Does XML formatting change the data or semantics?
- No. Formatting only adds whitespace between elements. Attribute values, text content, CDATA sections, and namespace prefixes are all preserved exactly as written.
- Is my XML private?
- Yes — all processing happens in your browser via JavaScript. Your XML document is never transmitted to a server, even for well-formedness checking.
- Why does my XML fail to format?
- Common issues: unclosed tags, mismatched open/close tag names, unquoted attribute values, or unescaped special characters in text content. Use < for <, > for >, and & for & in text nodes.
- Can it handle XML with namespaces?
- Yes. Namespace declarations (xmlns:prefix='...') and prefixed tags (prefix:element) are handled correctly and preserved in the formatted output.
- What's the difference between well-formed and valid XML?
- Well-formed means correctly nested tags, a single root element, and properly quoted attributes. Valid means it also conforms to a DTD or XML Schema. This tool checks well-formedness.
- Why is my XML declaration or encoding lost or changed?
- Because the document is re-serialised from the parsed tree, and the writer emits its own declaration. Verify the encoding on the way out — a file declaring one encoding while holding bytes in another is the usual source of mojibake.
- What is an XXE vulnerability?
- An external entity in a document instructing the parser to read a local file or fetch a URL, turning a parse into data exfiltration. It is why parsers should disable external entity resolution — this tool formats without expanding them.
Common errors and gotchas
- Reindenting inside an element whose whitespace is significant, which changes the data rather than the layout.
- Assuming well-formed means valid. A schema can still reject a document that parses perfectly.
- Losing a CDATA section's exact contents by reformatting through it.
- Overlooking that attribute order is not significant, then diffing two formatted documents and seeing noise.
- Feeding in HTML and expecting XML rules to apply. Unclosed tags are legal in one and fatal in the other.