XML Formatter & Beautifier Online - Professional 2026 Edition
Format, validate, and beautify messy XML with custom indentation. Detect syntax errors instantly with our 2026 AI-ready debugger. 100% Private & Free.
Key Features
- ✅ Auto-indentation
- ✅ Syntax highlighting
- ✅ Error detection
- ✅ File upload
- ✅ Copy/Download
How to Use
- Copy or paste your XML content
- Select your preferred indentation size (2, 4 spaces, or tabs)
- Click Format to apply formatting
- Preview the formatted XML
- Configure advanced options if needed (namespace handling, attribute wrapping)
- Copy the output or download as .xml file
- Use in your application or editor
- Version control the formatted XML for consistency
Expert FAQ
- Unlike JSON, XML whitespace can be meaningful. Won't re-indenting break mixed content?
It can, which is why this formatter only adds indentation between elements that have no text siblings — when an element mixes text and child tags (e.g. <p>Click <a>here</a> to continue</p>), it is left untouched rather than re-wrapped, because inserting newlines there would change the rendered/parsed text. Pure "data" XML (config files, API payloads) reformats freely since whitespace between tags is almost always insignificant there. - What happens to CDATA sections and comments?
Both are preserved byte-for-byte inside their delimiters (<![CDATA[ ... ]]> and <!-- ... -->) — the formatter never reflows the contents of a CDATA block, since that section is explicitly there to hold pre-formatted or escaped content (embedded HTML, JS snippets, etc.) that must survive unchanged. - Does it normalize self-closing tags like <br/> vs <br></br>?
No — it preserves whichever form was in the source rather than rewriting one into the other. Some XML consumers (older parsers, certain SOAP toolkits) are inconsistent about treating the two as equivalent, so silently "normalizing" them is a common source of formatter-introduced regressions that this tool deliberately avoids. - My XML has a DOCTYPE and processing instructions (<?xml-stylesheet ...?>) — will formatting strip them?
No, the prolog (<?xml version="1.0"?>), DOCTYPE declaration, and any processing instructions are kept in place at the top of the document. Stripping these is a real risk with some "quick" online formatters and can silently change how a downstream XML processor interprets encoding or applies a stylesheet.
Technical Details
Formatting XML is meaningfully harder to get right than formatting JSON, because JSON whitespace is never semantically significant while XML whitespace sometimes is. A naive formatter that blindly re-indents every tag will corrupt documents containing mixed content (text interleaved with inline elements, e.g. legal or documentation XML, XHTML fragments, DocBook) by inserting newlines and spaces into what was meant to be continuous text. This formatter detects mixed-content nodes and leaves them untouched, while still fully re-indenting "data-style" XML (the common case: SOAP envelopes, RSS/Atom feeds, config files, WSDL, Android/Maven XML) where inter-tag whitespace carries no meaning. CDATA blocks, comments, the XML prolog, and DOCTYPE declarations are preserved verbatim rather than reflowed or stripped — all are common places where lossy formatters introduce subtle bugs. Attribute handling is also configurable: documents with many attributes per element (common in Android layout XML or MSBuild project files) can wrap one attribute per line for reviewable diffs, while simpler documents keep attributes inline. If your XML fails to format cleanly, run it through the XML Validator first — the formatter assumes well-formed input and will surface the same syntax error rather than guessing at a malformed document's intended structure.