XML Validator

Check XML for well-formedness errors with precise line and column numbers. Flags empty elements, missing XML declarations, and deep nesting. Shows a collapsible tree view of valid XML structure.

Paste your XML above and click Validate XML to see the result.

About the XML Validator

This free online XML validator checks whether your XML is well-formed according to the W3C XML 1.0 specification. It pinpoints exactly where errors occur and flags structural issues that may cause problems when parsing or processing XML in applications.

Features

Validates XML well-formedness using the W3C XML specification
Precise error reporting — line number, column number, and description
Flags empty elements, missing XML declarations, and deeply nested structures
Collapsible tree view — explore the full element hierarchy interactively
Shows element count, attribute count, comment count, max depth, and file size
Expand all / collapse all tree controls
100% client-side — your data never leaves your browser

How to use

Paste your XML into the input box (or click Sample to load an example).
Click Validate XML.
If invalid, the error banner shows the line, column, and description of the problem.
If valid, a collapsible tree view lets you explore the element hierarchy interactively.

Common XML errors

Unclosed tags — every opening tag <item> needs a matching closing tag </item> or must be self-closed <item />.
Multiple root elements — a valid XML document must have exactly one root element.
Unquoted attributes — all attribute values must be wrapped in single or double quotes.
Unescaped special characters — use &, <, >, ", ' inside element content and attribute values.
Invalid tag names — tag names must start with a letter or underscore, not a number or special character.
Case sensitivity — XML is case-sensitive; <Item> and <item> are different elements.