XML Validator — Free Online XML Syntax Checker & Validator

XML validation ensures a document is syntactically correct and can be parsed without errors. A well-formed XML document follows all XML specification rules: a single root element, properly nested and closed tags, quoted attribute values, and escaped special characters (<, >, &, ", ').

The validator uses the browser's built-in DOMParser with text/xml MIME type. When parsing fails, the parser returns a parsererror document with a diagnostic message indicating the error type and location. This gives precise, actionable feedback — unlike some validators that only report "invalid XML."

The right panel shows formatted XML for valid input, making it easy to review structure after validation. This is particularly useful when debugging SOAP envelopes, Maven POM files, Android manifests, Spring configuration, or any XML-based configuration format.