XML Formatter & Validator

What is XML Formatter?

An XML formatter takes minified or messy XML and re-indents it with consistent nesting so the structure is readable. It also validates well-formedness — flagging unclosed tags, mismatched elements, and malformed attributes. XML remains common in SOAP APIs, RSS/Atom feeds, SVG, Android layouts, Maven POMs, and countless config files, making a reliable formatter a daily need.

How to format XML online

1. 1Paste your raw or minified XML into the input pane.
2. 2The tool re-indents it and reports any well-formedness errors.
3. 3Choose your indent size (2 spaces, 4 spaces, or tabs).
4. 4Copy the formatted XML into your editor, feed, or config file.

Use Cases

Code Examples

<note><to>Ada</to><from>Grace</from></note>

<note>
  <to>Ada</to>
  <from>Grace</from>
</note>

Key Concepts

Well-formed vs valid

Well-formed means syntactically correct (tags nest and close). Valid means it also conforms to a DTD or XSD schema. This tool checks well-formedness.

CDATA

A <![CDATA[ ... ]]> section holds text that should not be parsed as markup — useful for embedding code or HTML. It's preserved verbatim.

Namespaces

Prefixes like xmlns:soap disambiguate element names from different vocabularies. Formatting keeps them intact.

Tips & Best Practices

• ▸Whitespace between elements is normalized, but whitespace inside text nodes may be significant — verify mixed content.
• ▸CDATA and comments are preserved exactly; only inter-element indentation changes.
• ▸If validation fails, the first mismatched or unclosed tag is usually the real culprit — start there.
• ▸For huge XML documents, a streaming parser (SAX) in code scales better than loading everything into memory.