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Paste a complete XML document, including its single root element.
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XML Validator
Check whether XML is well-formed and locate syntax errors such as mismatched tags, invalid nesting, broken attributes and multiple root elements.
Parse a complete XML document Detect mismatched and unclosed tags Detect invalid attribute syntax Require one document element
Tips
Start with the example, then replace it with your complete source.
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INPUT XML document to validate *
Paste a complete XML document, including its single root element. Example: <catalog><tool id="1">Formatter</tool></catalog>
Reading file…
Validation result
About the tool
What XML Validator does
XML Validator checks whether a document is well-formed XML. It catches malformed tags, invalid nesting, duplicate or broken attributes, text that is illegal in the current context and documents without one valid root element.
When parsing fails, the result reports the first available XML parser message with its line and column. When it succeeds, the result is Valid XML. This is a syntax check only: it does not validate the document against an XSD, DTD content model or application-specific rule set.
How to use
- Paste complete XML. Include the declaration and document element when they are part of the source.
- Run validation. The parser reads the XML with network access disabled.
- Locate the error. Use the returned message, line and column as the starting point.
- Correct and rerun. One early syntax error can cause later messages, so validate after each correction.
- Check the data contract. Use the required XSD, DTD-aware process or destination application after well-formedness passes.
Built for the task
Why use XML Validator?
Focused controls, predictable output, and a workflow designed around this exact transformation.
01
Well-formedness verdict
Confirm that the complete source can be parsed as an XML document.
02
Line and column detail
Start correction at the parser location instead of scanning the whole file manually.
03
Nesting checks
Detect closing tags and element hierarchy that do not match the source structure.
04
No network retrieval
External network access is disabled during the XML parsing step.
Useful answers
Questions about XML Validator
Practical details about input, output, privacy, limits, and the best way to use this tool.
01 What does Valid XML mean here?
It means the source is well-formed and the XML parser can construct a document. It does not mean the data satisfies a schema or business rules.
02 Does this validate XSD?
No. XSD validation is not part of this tool.
03 Does it validate a DTD content model?
No. Use a dedicated, securely configured DTD-aware validator when that is required.
04 Are line and column exact?
They identify the parser location for the first reported problem. The true cause can begin earlier, especially with broken quotes or nesting.
05 Can XML have more than one root element?
No. A well-formed document has one document element containing any nested content.
06 Are XML names case-sensitive?
Yes. For example, <Item> and <item> are different names.
07 Does formatting make invalid XML valid?
No. A formatter must parse the document too; fix syntax errors before relying on formatting.
08 Is external network access allowed while parsing?
No. The parser is called with network access disabled.
Learn XML
Read the complete XML Guide
Understand XML syntax, elements, attributes, namespaces, validation, formatting, parsing, security, and common errors.
- Elements, attributes, and namespaces
- Formatting and validation
- Parsing, security, and debugging
Read guide
Practical explanations and examples
Well-formed XML rules
A document needs one root element, correctly nested start and end tags, quoted attribute values and legal XML characters. Element and attribute names are case-sensitive. Reserved characters in text and attributes must be escaped where required.
Using line and column errors
The reported location is the point where the parser could no longer continue confidently. Check that position and the preceding opening tag, quote or entity reference. Fix the earliest structural issue first because it may cause several apparent errors later in the document.
Syntax validation versus schema validation
Well-formedness answers whether the source is syntactically XML. XSD or other contract validation answers whether the elements, attributes, order and values match a particular vocabulary. A document can pass this tool and still fail the schema required by an API, feed or importer.
DOCTYPE and external resources
The XML parser runs with network access disabled. Do not treat this utility as a DTD validation service or as a safe way to resolve external entities. Production XML processing should keep external resource loading disabled unless a narrowly controlled use case requires it.
Continue the XML workflow
After syntax validation, use XML Formatter to indent the document, XPath Tester to query the parsed tree, or XML to JSON when the receiving workflow requires JSON. Review conversion rules because XML attributes, repeated elements and mixed content do not have one universal JSON mapping.
XML specification and privacy
The formal well-formedness requirements are defined by the W3C XML specification. Remove credentials, private customer records and other sensitive values from production XML before using any online utility.