XML Input

Output

Before touching the layout, this tool validates your document with the browser's real XML parser (DOMParser in application/xml mode) and shows the first two lines of the parser error if it fails. Only well-formed XML gets reformatted — a two-space indent per nesting level, one tag per line wherever tags are adjacent.

Validation is a real parse, not tag counting

Because a genuine XML parser runs first, this catches the errors regex-based pretty-printers miss: mismatched case (<Item> closed by </item> — XML is case-sensitive), a second root element after the first one closes, and attribute values missing quotes. The one that surprises people most is entities: XML predefines exactly five (&, <, >, ', "), so   — perfectly legal in HTML — is an undeclared-entity error here unless your document declares it in a DTD.

That same strictness means this is the wrong tool for ordinary HTML. Void elements like and <img> without self-closing slashes are well-formed HTML but fatal XML errors. It works well on XHTML, SVG, RSS feeds, Maven POMs, and Android layout files — anything that is actually XML.

How the indenter treats mixed content and minify treats whitespace

The reformatter only breaks lines between adjacent tags (>< with nothing but whitespace between). An element mixing text and inline tags — Hello world again — stays on one line untouched, which is correct: splitting it would inject whitespace into your text content. Declarations, comments, and self-closing tags never increase depth.

Minify is more aggressive than Format: it removes whitespace between tags and also collapses any run of two or more whitespace characters to a single space, including inside text nodes. If your document carries whitespace-significant content — xml:space="preserve" is not honored — minify will alter it, so keep such documents to Format only.

Format a single-line document

Input: <?xml version="1.0"?><catalog><book id="bk101"><title>XML Guide</title><price>29.95</price></book></catalog>

Output: <?xml version="1.0"?> <catalog> <book id="bk101"> <title>XML Guide</title> <price>29.95</price> </book> </catalog>

The <?xml?> declaration stays at depth zero; attributes are left in their original order.

Good to know: If a document fails with an entity error, the fastest fix is usually numeric character references: replace   with  , which is valid in any XML document without a DTD.

For ordinary HTML — the documents this validator rejects — the code minifier's HTML mode is the right tool, and the JSON formatter applies the same validate-first discipline to JSON payloads.