Format, minify and check XML

XML still runs a lot of the world: sitemaps and RSS feeds, SOAP and banking APIs, e-invoices, Android layouts, Office documents, SVG and countless configuration files. It usually arrives as one long line or with indentation that no longer matches the nesting. This formatter puts each element on its own line, indents children under their parent, keeps short text-only elements such as <title>Report</title> on one line, and leaves the XML declaration, comments, CDATA sections and doctype intact.

Before formatting, the document is checked for well-formedness: every start tag has a matching end tag in the right order, attribute values are quoted and not repeated, ampersands are written as entities, and there is exactly one root element. If anything is wrong you get a message such as "Expected </item> but found </list>" with the line and column, and the offending line shown with a caret, which is often faster than reading a stack trace from the program that rejected the file. The facts panel shows the root element, the number of elements and the deepest nesting.

Minify mode does the opposite: it removes whitespace between tags while keeping text content exactly as written, and can drop comments too. Note that well-formed is not the same as valid: this tool does not check a DTD or XML Schema, so a file can pass here and still be rejected by a system that expects particular elements. The formatter is a small purpose-built parser that runs in your browser; nothing is uploaded.