Validate XML Online
Validate XML online and get a clear pass or fail result so syntax errors in feed data, API payloads, config files, and structured markup are caught before use. Paste your XML and the validator checks that it is well-formed — matching tags, quoted attributes, a single root element — and returns a readable result.
How to use XML Validator
Paste content into the xml input panel.
Run the validator to check for success messages, syntax issues, or invalid structure.
Review the result, then copy or download it if you need to share the outcome.
Why this helps in real workflows
An XML feed or API response is failing to parse in your application and you want to confirm whether the XML itself is malformed.
A config file written by hand or edited in a text editor needs a syntax check before it is deployed or committed.
An XML export from a CMS, ERP, or data pipeline tool needs to be validated before it is imported into another system.
You are building or debugging a SOAP integration and want to verify that the request or response XML is well-formed before investigating further.
Common problems and fixes
The validator returns an error but I cannot see what is wrong.
The error message includes the line number and a description of the problem. Common issues are unclosed tags, mismatched tag names, bare & or < characters outside CDATA, missing quotes around attribute values, or more than one root element.
The XML has a namespace prefix and the validator rejects it.
Namespace prefixes are valid XML but the namespace URI must be declared with an xmlns attribute on the element or an ancestor. If the xmlns declaration is missing, the XML is not well-formed and the validator will reject it.
The XML passes validation but still fails in my application.
Well-formedness validation only checks that the XML follows basic syntax rules. Your application may also require schema validation — checking that the correct elements, attributes, and data types are present. This tool checks well-formedness only.
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Frequently asked questions
How do I validate XML?
Paste your XML into the input box, run the validator, and review the validation result in the output panel.
Will the XML validator show syntax errors?
Yes. Invalid XML returns an error message with a description of the problem so you can find and fix the issue.
Is this XML validator free?
Yes. It is free to use in your browser.
What is the difference between well-formed XML and valid XML?
Well-formed XML follows basic syntax rules — matching tags, quoted attributes, a single root element. Valid XML is also well-formed but additionally conforms to a specific schema (DTD or XSD). This tool checks well-formedness.
Can I use this to validate XML against a schema?
No. This tool checks whether XML is well-formed. Schema validation against a DTD or XSD requires a schema-aware validator.
Can I format the XML after validating it?
Yes. Once you confirm the XML is valid, paste it into the XML Formatter to add readable indentation.