XML Validator

About this tool

Check whether your XML is well-formed using the browser's XML parser. Errors are reported with their location.

Example

Input: <a><b>x</b></a>

Output: Well-formed XML

Privacy

This tool runs entirely in your browser. Your data is processed locally and never uploaded to a server.

How to use this tool

1. Paste your XML into the input box.
2. Click Validate to check the document.
3. Read the result panel to see whether the XML is well-formed.
4. If there is an error, jump to the reported line and column in your XML and fix that spot.

Step by step, what happens

1. The tool sends your XML to the browser's built-in XML parser.
2. It checks whether the document is well-formed, not whether the tags match a schema or business rule.
3. If the parser finds a problem, the tool shows the parser message and the location where it stopped.
4. If the XML is valid, the tool confirms that the input is well-formed.

Worked example

A common check is making sure an opening tag has the matching closing tag.

Input: <note><to>Sam</to><from>Alex</from></note>

1. Paste the XML into the validator and run the check.
2. The browser parser reads the tags and verifies that they are properly nested and closed.
3. Because every tag is matched, the tool reports that the XML is well-formed.

Tips and common mistakes

• If the tool reports an error, use the line and column to find the exact spot instead of scanning the whole file by eye.
• This validator checks well-formedness only, so it will not tell you whether your XML follows a custom schema.
• Make sure your XML has one root element and that every opening tag has a closing tag unless it is self-closing.
• Watch for unescaped characters like < and & inside text, because they often trigger parser errors.

Frequently asked questions