XML Validator
Find basic XML syntax problems such as mismatched tags, broken nesting, or invalid attribute quoting.
Check XML well-formedness: one root element, properly nested tags, and correctly quoted attributes.
Checks syntax, not an XSD, DTD, or application schema. Input remains in your browser.
🔒 All processing happens in your browser — files never leave your device. Your input stays in this browser and is not uploaded to Smart Online Tools.
How it works
- Paste XML into the editor.
- Select Validate XML.
- Review the parser message or root element result.
Good to know: This checks well-formedness only; it does not validate against an XSD, DTD, or application schema.
Privacy and processing
All processing happens in your browser — files never leave your device. Your input stays in this browser and is not uploaded to Smart Online Tools.
Well-formed XML versus schema validation
A well-formed XML document has exactly one document element, properly nested tags, and valid markup. That is different from schema validation, which checks whether elements and attributes match a domain-specific XSD or DTD.
This tool runs the browser's XML parser and reports whether it can build a document tree. It does not fetch external schemas or load remote entities.
Frequently asked questions
What does XML Validator do?
Check whether an XML document is well-formed. Find basic XML syntax problems such as mismatched tags, broken nesting, or invalid attribute quoting.
Does this tool upload my files or input?
Your input stays in this browser and is not uploaded to Smart Online Tools.
What should I know before using this tool?
This checks well-formedness only; it does not validate against an XSD, DTD, or application schema.