Free XML Validator

How to Validate XML Online

Paste your XML into the left panel and the validation result appears instantly on the right. A green checkmark means your XML is well-formed. A red error shows the exact problem with line and column numbers. You can also drag and drop an .xml file or use the upload button.

Common XML Syntax Errors

The most frequent XML errors are: unclosed or mismatched tags (e.g., <div> closed with </span>), unescaped ampersands in text content (use &amp; instead of &), unescaped less-than signs (use &lt;), missing quotes around attribute values, duplicate attributes on the same element, and invalid characters in tag names.

Frequently Asked Questions

What does an XML validator do?

An XML validator checks whether your XML is well-formed according to the XML specification. It catches unclosed tags, mismatched tag names, missing attributes, and other structural errors.

Is this XML validator free?

Yes — completely free, forever. No sign-up, no account, no usage limits.

Is my data safe?

All validation happens locally in your browser using JavaScript. Your XML is never uploaded to any server. It's safe to use with sensitive or proprietary data.

Does it show where the error is?

Yes — when your XML is invalid, the validator shows the error message along with the line and column number where the problem was detected.

What does 'well-formed' mean?

Well-formed XML follows basic syntax rules: every opening tag has a closing tag, tags are properly nested, attribute values are quoted, and special characters are escaped. This is different from schema validation, which checks whether the XML matches a specific schema (XSD).

Does it validate against an XSD schema?

No — this tool checks whether your XML is well-formed (syntactically correct). Schema validation against XSD or DTD requires server-side processing and is not supported in this privacy-first browser tool.

What are common XML errors?

The most common XML errors are: unclosed tags, mismatched opening and closing tag names, unescaped ampersands (&) or less-than signs (<) in text content, missing quotes around attribute values, and duplicate attributes on the same element.

Can I also format my XML?

Yes — use the XML Formatter to pretty-print or minify your XML with configurable indentation.