Have you ever opened an XML file that sits on one long line? It is hard to scan and even harder to debug. XML Pretty Print takes that cramped markup and lays it out with clean indentation.
This tool is for developers, QA testers, and students who work with XML. You paste raw or minified XML, and the formatted version appears as you type.
Table of Contents
- What the Tool Does
- How to Use It, Step by Step
- How the Formatter Works
- Worked Example
- How to Read the Results
- Tips and What It Does Not Check
- Limitations and Assumptions
- FAQs About the XML Pretty Print
What the Tool Does
The tool parses your XML in the browser and rebuilds it with tidy indentation. It gives each tag its own line. Three cards above the boxes report size and line details.
- Live Formatting: it reads the Raw XML Input box and reformats as you type.
- Two-Space Indent: each level of nesting moves in by two spaces.
- One Tag Per Line: elements, comments, and the XML declaration each get a line.
- Well-Formed Check: it flags broken markup with an inline message.
- Size Cards: it shows Original Length, Formatted Size, and Output Lines.
- Two Buttons: Clear empties the input, and Copy XML copies the output.
How to Use It, Step by Step
- Paste your XML into the Raw XML Input box on the left. A sample catalog loads by default.
- Watch the Pretty Printed XML Output box fill in on the right as you type.
- Read the three cards for the input size, the output size, and the line count.
- Press Copy XML to send the formatted text to your clipboard.
- Press Clear to empty the input and reset the three cards to zero.
How the Formatter Works
The formatter parses your text into a document tree, then writes it back out. It reads the structure first, so it knows which tags nest inside others. Each child tag moves in two more spaces than its parent.
Raw XML→Parse to DOM→Add 2 Spaces Per Level=Formatted XML
- It parses the input into a document object model before writing output.
- A tag that opens an element adds one indent level of two spaces.
- A matching closing tag returns to its parent level.
- Self-closing tags and the XML declaration keep the current level.
Worked Example
Jordan pastes a short order file that sits on one line. The raw text is 71 bytes long with no line breaks. The tool nests each element under its parent.
| Card | What It Counts | Output |
|---|
| Original Length | bytes you pasted | 71 B |
| Formatted Size | bytes after indenting | 102 B |
| Output Lines | tags on their own lines | 8 |
The output puts order at the left edge, then items two spaces in, then item two more. The name and qty tags sit deepest, at six spaces. The default catalog sample behaves the same way. It starts at 159 bytes and expands to 186 bytes across 8 lines.
How to Read the Results
Original Length is the byte count of the text you pasted. It measures true UTF-8 bytes, so the B label matches non-English text too.
Formatted Size is the byte count after indenting. It is almost always larger than the input, because new lines and spaces are added.
Output Lines is how many lines the output has. In clean XML this is one line per tag, plus any text lines.
Tips and What It Does Not Check
This tool catches broken markup and then formats the rest. If a tag is missing or mismatched, it shows an inline error and clears the output. Use it for reading, sharing, and a fast syntax check.
More utilities live in the developer tools hub.
Limitations and Assumptions
- It checks well-formedness only. It does not confirm your file against a schema or a DTD.
- Mixed content stays on one line. An element with both text and child tags is not deeply indented.
- Insignificant whitespace between element-only tags is normalized during formatting.
- Output line endings use a single line feed, the Unix style.
- The size cards count true UTF-8 bytes, so emoji and accented letters add up correctly.
- The Copy button falls back to a hidden copy and always shows a visible result.
FAQs About the XML Pretty Print
Does XML Pretty Print Check If My XML Is Valid?
It confirms your markup is well formed, meaning every tag opens and closes correctly. It does not check your file against a schema or a DTD. Those deeper rules need a dedicated validator.
What Happens When My XML Has an Error?
The output clears and a red message appears above the boxes. The message names the Raw XML Input field and adds the parser reason when one is available. Fix the markup and the output returns.
Is There a Button to Format the XML?
No. The output updates on its own as you type or paste. The only buttons are Clear and Copy XML.
Does the Tool Send My XML Anywhere?
No. All formatting runs in your browser. Nothing is uploaded, saved, or shared with a server.
Does It Keep My XML Declaration?
Yes. A leading declaration line stays at the top of the output. The rest of the tree is indented below it.
Can I Format a Whole XML File?
You can paste the file contents into the box. Very large files may feel slow, since the whole text is reprocessed on each keystroke.
This calculator gives general estimates only and is not professional advice. Reviewed for general accuracy by Prof. Dr. Khalil Mudassar, PhD.