How to Validate XML in Your Browser
Paste Your XML
Copy your XML document or fragment into the input area. The validator reads the whole text you paste, so include the XML declaration and the single root element if you have them. Everything stays on your device.
Click Validate XML
Press the Validate XML button. The tool parses your text with the browser's built-in DOMParser and checks for well-formedness: closed tags, correct nesting, quoted attributes, and one root element.
Read the Result
A green banner confirms valid XML and reports the root element name plus the total element count. A red banner shows the first parser error message so you can jump straight to the problem. Use Clear to reset and check another document.
What This Validator Checks and What It Does Not
This tool verifies well-formedness using the same XML parser your browser ships with. It does not perform schema validation against a DTD or XSD. The table below shows where each rule falls so you know what a passing result actually guarantees.
| Rule or Feature | Checked Here | Notes |
|---|---|---|
| Tags closed and correctly nested | Yes | Mismatched or unclosed tags are reported as errors. |
| Single root element | Yes | Multiple top-level elements fail well-formedness. |
| Attribute values quoted | Yes | Unquoted attribute values trigger a parser error. |
| Escaping of and , and special characters | Yes | Raw and or unescaped less-than signs are flagged. |
| Namespace prefixes declared | Yes | Undeclared xmlns prefixes cause an error. |
| Conformance to a DTD or XSD schema | No | Schema validation needs a separate server-side tool. |
Is This the Right Tool for Your Task
Quick Syntax Check
If you just need to confirm an XML file parses cleanly before using it, this is ideal. You get the root name and element count the moment it is well-formed.
Debugging a Parse Error
When another program rejects your XML, paste it here. The first parser error message points you to the unclosed tag, stray character, or bad nesting causing the failure.
Sensitive Config Files
Because validation runs entirely in your browser with DOMParser, the content stays on your device. That makes it suitable for checking config files without uploading them.
Schema or DTD Validation
If you must confirm the document matches a defined XSD or DTD structure, this tool is not enough. Use a dedicated schema validator that supports those grammars.
Common Problems and Fixes
Error mentions an extra content at the end of the document
This usually means you have more than one root element. Wrap all top-level elements in a single container element so the document has exactly one root.
Error about an unexpected character or entity
A raw and, less-than, or greater-than sign in your text breaks parsing. Replace them with &, <, and >, or place the content inside a CDATA section.
Result says a tag was not closed
Check that every opening tag has a matching closing tag and that nesting is correct. Self-closing elements must end with a slash, such as a br element written as a slash before the closing bracket.
Namespace prefix error appears
Every prefix used on an element or attribute must be declared with a matching xmlns attribute in scope. Add the missing xmlns declaration on the element or an ancestor.