XML Formatter
Tidy Indents, a One-Line Version and a Syntax Check

Jobs This XML Formatter Handles for You

This XML formatter takes XML that arrives on one long line, or indented in five different styles, and lays it out neatly, the way a pretty print of the same file would look. Each element gets its own line, children sit one step to the right, and short text stays next to its tag, so the syntax is easy to read at a glance.

It doubles as an XML well-formedness checker. Before it formats anything, it checks every tag, attribute and entity. If something is wrong, you see the line and the column, a plain explanation, and a button that puts the cursor right on the spot.

The Denwix formatter never sends the XML anywhere. Therefore, your config files, feeds and API replies never leave your computer, which matters when they contain keys, prices or customer data.

What Formatting Actually Changes

Formatting touches nothing but the spacing between tags. The names, the attributes, the text and the order of everything stay exactly as they were. A program that reads the file sees the same data before and after, so you can format with confidence.

The rules follow the W3C XML specification, the standard every XML reader is built on. That is also why the checks are strict: a file that passes here will open in any tool that follows the same rules.

Format XML Without Losing Anything

Many formatters quietly drop comments, CDATA sections or the DOCTYPE, because their parser was never built to keep them. This one keeps all of them in place. Comments stay where you wrote them, and CDATA blocks keep their content untouched.

Two cases get extra care. The formatter copies elements marked xml:space="preserve" exactly, spaces and line breaks included. Moreover, an element that mixes text with tags, such as a paragraph with a bold word inside, stays on one line as written, since adding line breaks there would change the text.

An XML Validator That Points to the Line

Knowing that a file is broken is only half the answer. The checks table lists every problem with its line and column: a closing tag that does not match, an attribute without quotes, a lone ampersand, or a second root element. Each one comes with a sentence that explains the fix.

Press Show me where, and the cursor jumps to the first problem in your XML. Because one mistake often causes the next, fixing the first one and checking again usually clears several rows at once.

Shrink XML Into a Single Compact Line

Choose One line (minified) in the indent menu, and the tool squeezes the XML onto a single line. All whitespace between tags goes, while text keeps its words and a single space where it had several. One switch keeps or drops the comments.

The checks table then shows the size before and after. Smaller XML loads faster in feeds and API replies, although for readability you will usually want the formatted version while you work on it.

Why Well-Formed XML Can Still Fail Validation

XML people use two words that sound alike. Well formed means the file follows the basic rules of XML, and every reader needs that. Valid means it also matches a schema, such as an XSD, which describes which elements a particular format allows. This tool checks the first, the part every file must pass.

How the XML Validator Reads Your File

The XML validator reads your file from the first character to the last, the way a strict parser would. It checks that the declaration comes first, that every name starts with a letter, that every attribute has a quoted value, and that no attribute appears twice on one tag.

Then it follows the nesting. Each opening tag waits for its partner, and the validator notes where a tag closes in the wrong order or never closes at all. Finally, it looks at every ampersand and every entity, since those cause more broken feeds than anything else. Because it reads rather than guesses, a file that passes here will also pass in the program that needs it.

Frequent XML Errors and Their Fixes

The most frequent error is an ampersand written on its own, as in Tom & Jerry. XML reserves that sign, so you must write it as & instead. Likewise, a less-than sign inside text has to become <. XML does not define entities from HTML, such as  , either, so use a number like   instead.

Next come tags that close in the wrong order and attributes without quotes. Names also matter, since XML is case sensitive and a closing tag must match its opening tag letter for letter. Namespaced names such as xs:element are fine, and the namespaces recommendation explains how those prefixes work.

Places XML Is Still Everywhere

XML is older than JSON, yet it is everywhere. Sitemaps, RSS and Atom feeds, SVG images, Office documents, Android layouts, Maven and .NET project files, SOAP services and many bank and government interfaces all use it. For a gentle overview, MDN’s introduction to XML is a good start.

When you need the data somewhere else, our XML to JSON converter turns it into JSON in one step. And when a sitemap is the file in question, the sitemap generator builds a correct one from a list of links.