XML Formatter and Validator

How to use it

1. 1Paste your text into the box marked "Your XML"Paste a document, a fragment, an API response — it does not have to be valid yet. Everything happens inside your browser — nothing is uploaded, so there is nothing for us to store, log or lose.
2. 2Read the result as it updatesThere is no button to press. Choose Format to indent the document or Minify to strip it down, and the result appears immediately underneath. The output recomputes every time you change the text or one of the options above it.
3. 3Set the indentation with the Indent controlTwo spaces, four spaces or a tab. It reformats as soon as you change it, so you can see which one your document reads best in.
4. 4Read the error position when it is not well-formedThe message names the character where parsing stopped. The actual mistake is usually just before it — most often a tag that was never closed.
5. 5Check the notes about what was left aloneMixed content and anything marked xml:space="preserve" are not re-indented, because there the whitespace is part of the data. The notes say when that applied, so an unchanged section is explained rather than looking like a bug.
6. 6Copy or download the resultThe buttons under the output put it on your clipboard or save it as a file, and each one says exactly what it will copy or download. Any note about something the tool changed or deliberately left alone is shown with the result rather than hidden.

About this tool

Paste XML and get it back either neatly indented or minified — and if it is not well-formed, an error message that names the problem and points at the exact character where parsing stopped.

The formatter is deliberately conservative about what it touches. Only insignificant whitespace is changed: the indentation between elements and the decorative edges of text-only content. Mixed content — an element containing both text and markup, like a paragraph with bold words in it — is left exactly as written, because the whitespace between text and tags is part of the text. Content marked xml:space="preserve" and everything inside CDATA sections comes through byte for byte.

Understanding the result

A formatted or minified result means the document is well-formed: every tag closes, every attribute is quoted, entities are complete, and there is exactly one root element. That is XML's minimum bar, and it is what parsers require before they will read the file at all.

An error names what is wrong and where. The position points at the character where parsing stopped — the actual mistake is often just before it, such as the tag that was never closed.

The "worth knowing" notes list anything the tool did or deliberately declined to do, such as leaving mixed content alone or accepting an entity because a DTD might define it.

Example

<order id="42"><item sku="A1"><qty>2</qty></item></order>

<order id="42">
  <item sku="A1">
    <qty>2</qty>
  </item>
</order>

Limitations

• This checks well-formedness, not validity. Validating against a DTD or an XML Schema requires the schema itself, and claiming a document is "valid" without one would promise more than the tool checks.
• Entities beyond the five XML defines are only accepted when the document carries a DTD internal subset that could declare them — and the tool says it did not check the declaration, because it does not read external DTDs.
• Attribute order and quoting are preserved, never normalised. A formatter that rewrites attributes is making changes nobody asked for.
• Very large documents are bounded by your browser's memory. For multi-megabyte files, a command-line tool such as xmllint is the right instrument.

Questions