XML Validator

About This Tool

The XML Validator checks whether your XML document is well-formed according to the XML specification. It detects common errors including unclosed tags, mismatched element names, invalid character usage, and missing root elements. The error output includes the line number and a context snippet so you can pinpoint and fix the problem quickly.

Validation uses the browser's built-in DOMParser — no XML is sent to any server. Your data stays private. Note that this tool checks well-formedness only, not schema validity (XSD or DTD). For schema validation, use a server-side tool or an IDE plugin.

How to Use

1. Paste your XML into the input area, or click Sample (Valid) or Sample (Errors) to load an example.
2. Click Validate to run the check.
3. If errors are found, the error message and line number are shown with a context snippet.
4. Fix the issue in your XML editor and re-validate until you see “Valid XML”.

Use Cases

Backend developers working with XML APIs or configuration files validate documents before deploying to catch parsing failures in production. Data engineers processing XML feeds validate samples to ensure structural integrity. Front-end developers embedding SVG or XHTML validate snippets before pasting into HTML. Anyone editing XML config files manually uses this to catch typos before restarting a service.

FAQ

• What is well-formedness? — A well-formed XML document follows the basic XML syntax rules: one root element, properly nested and closed tags, quoted attributes, and no illegal characters. Well-formedness is a prerequisite for schema validation.
• Does this validate against XSD or DTD schemas? — No. This tool checks structural well-formedness only. For XSD or DTD validation, use a full XML processor like Saxon or an IDE plugin.
• Why does valid XML still cause issues in my application?— A document can be well-formed but still fail schema validation (wrong element names, missing required fields). Check your application's schema definition for those errors.
• Is my XML sent to a server?— No. The browser's built-in DOMParser handles all validation locally. Your XML never leaves your device.