XML Validator
Instantly check if your XML document is well-formed. Get clear error messages for any issues.
An invalid XML document will crash parsers, fail API calls, and cause hard-to-debug errors in applications. XML validation checks whether a document is well-formed — meaning it follows the basic structural rules of XML — before you use it in production. This tool uses the browser's native XML parser to immediately detect syntax errors, giving you precise error messages that pinpoint exactly what needs to be fixed in your XML document.
📋 How to Use This Calculator
Paste your XML into the input field and click "Validate XML." The tool parses the document using the browser's DOMParser with the "text/xml" MIME type. If the XML is valid, you see a green success message. If there is a problem, the error message from the parser appears in red — it typically includes the type of error and sometimes a line reference. Fix the issue, paste the corrected XML, and re-validate. Common fixes: add a missing closing tag, escape special characters (& < >), remove attributes without values, and ensure a single root element.
💡 Key Facts & Information
XML validation in this tool checks for well-formedness — the fundamental XML rules. Well-formedness does not guarantee business logic correctness; for that you need schema validation (XSD, DTD, or RelaxNG). Schema validation checks that elements appear in the right order, have the right types, and conform to constraints defined by the schema. Most XML-consuming APIs care about well-formedness first — a schema-invalid document can sometimes still be processed, but a malformed document will always be rejected. Well-formedness rules: proper nesting, matching tags, quoted attributes, single root element, and escaped special characters.