Validate XML syntax using the browser DOMParser. Check for well-formedness, view detailed error messages with line hints, and format/beautify XML with configurable indentation.
LevnTools XML Validator lets you format, validate, and transform your code directly in your browser. Everything runs locally in your browser — your code and data never leave your device. Unlike cloud-only alternatives that require uploads and accounts, this tool is completely free with no usage limits or watermarks. It is designed for developers debugging API responses, DevOps engineers working with configuration files, students learning data formats — anyone who needs a fast, reliable developer tool without the overhead of installing software. Just open the page and start working.
XML Validator is used by a wide range of people. Explore how different groups use this tool:
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The tool uses the browser built-in DOMParser to parse your XML as application/xml. If parsing fails, the DOMParser generates a parsererror element containing the error details which the tool displays.
The validator catches all XML well-formedness errors: unclosed tags, mismatched tag names, invalid characters, missing root element, duplicate attributes, and malformed declarations.
Yes. Click "Format" to validate and then re-indent your XML with your chosen indentation (2 or 4 spaces). The formatted output can be copied or applied back to the input area.
No. This tool checks XML well-formedness only (correct syntax). It does not validate against XSD, DTD, or RelaxNG schemas. For schema validation, use a dedicated XML schema validator.
Yes. All validation and formatting runs entirely in your browser using the native DOMParser API. No data is sent to any server. The tool works offline once the page is loaded.