📄 XML formatting and validation

Automatically formats XML data with indentation. Syntax errors are also detected.

✓Formatting complete
Errors found

Usage and Application Examples

  • Paste the XML code into the input area and click "Execute Formatting
  • If there is an error, an error message will be displayed
  • Select indentation type (space/tab) and format to your preference
  • Organized for easier viewing with comment removal and attribute sorting
  • Useful for checking and debugging API configuration files and configuration XML
  • Formatted results can be copied or downloaded to a file

What is XML Formatter?

This free online tool validates and automatically formats XML data with proper indentation, making unreadable single-line XML instantly readable. Using the browser's DOMParser API, it detects syntax errors immediately and reports the exact issue preventing XML from parsing. The tool supports multiple indentation options (spaces or tabs, 2 to 4-character widths) and handles XML declarations, comments, and special characters. Unlike text editors that treat XML as plain text, this validator ensures your XML conforms to W3C standards before deployment.

How to Use

Paste your XML code into the text area and click "Format". The tool instantly displays beautifully indented XML on the right side. If errors exist, a red error message shows the parsing failure reason and approximate location. Select your preferred indentation style (2-space, 4-space, tabs) from the dropdown menu, and the output updates immediately. Copy the formatted result directly or download as an .xml file. The preview panel shows exact character positions and structure depth, helping you visualize nested elements.

Use Cases

API developers debug SOAP XML requests sent between services, using the formatter to verify request structure matches WSDL specifications. Data analysts validate XML exports from legacy enterprise systems before importing into databases or data warehouses, catching malformed records immediately. Configuration file maintainers format Spring Framework XML configs or Maven pom.xml files, ensuring consistency across development teams. Web developers working with SVG graphics use the formatter to clean up exported files from design tools, removing unnecessary attributes and improving readability for version control diff visibility.

Common Mistakes & Solutions

Missing closing tags cause "unexpected end of file" errors—the formatter pinpoints the exact line where closing tags vanish. Solution: search for opening tags without matching closing tags. Improper character escaping breaks XML parsing; special characters like &, <, and > require &, <, and > entities. Solution: the error message identifies the problematic character position. Mixing quotes in attribute values creates parsing failures when an attribute contains both single and double quotes. Solution: escape inner quotes using entities or wrap carefully.

Tips & Insights

XML origins trace to SGML in the 1970s, designed for complex document markup with flexibility. Modern APIs prefer JSON for simplicity, but enterprises maintain massive XML systems because replacing them costs millions. XML excels at self-documenting data (element names describe content) and supports arbitrary nesting depth, unlike flat JSON structures. Proper indentation saves developer hours during debugging—a single mismatch in 500 lines becomes obvious when formatted. XSD schema validation goes beyond this formatter's scope, but proper indentation here ensures your XML passes DTD validators downstream.

Frequently Asked Questions

What is the difference between XML formatting and validation?

Formatting aligns indented for easy viewing. Validation checks for and reports syntax errors. This tool does both.

Is the XML declaration () required?

No, it can be processed without it. The tool automatically determines the presence or absence of a declaration.

Can you handle large XML files?

It can be processed as long as your browser's memory will allow. Avoid extremely large files (more than a few MB).

Is data transmitted?

No. All processing is completed within the browser. All processing is completed only in the browser. No data is sent to the server.

What indentation options are available?

The tool provides multiple indentation choices including spaces (2, 4, 8) and tabs. You can select your preferred indentation style before formatting, making the output compatible with your project's coding standards.

How does the tool handle XML namespaces?

Namespaces are preserved and properly formatted with their namespace prefixes intact. The tool maintains namespace declarations and attributes without modification, ensuring valid XML output.

Can it handle malformed XML?

The tool detects malformed XML and displays an error message with the line number where the issue occurs. This helps you quickly identify and fix problems before attempting to format the document.

What is CDATA and how is it handled?

CDATA (Character Data) sections are special XML constructs that allow you to include text with special characters without escaping. The tool preserves CDATA sections correctly and formats them without altering their content.

Can I customize the output format?

Yes, you can choose indentation style and amount. Some versions also allow you to remove unnecessary whitespace or adjust other formatting parameters depending on your specific needs.

Does the tool support XML Schema validation?

The tool focuses on formatting and basic syntax validation using DOMParser. Full XML Schema (XSD) validation is not supported, but it will catch structural errors and missing required elements.