Free XML Validator Online - No Signup

Check XML well-formedness locally and receive clear parser diagnostics, available line and column details, nearby source context, structural quality checks, document metrics, and exportable validation reports.

Validate XML See how it works
No XML uploads Detailed syntax errors Source-line context Text and JSON reports

XML Validator

Paste XML or open a strict UTF-8 file. Validation checks well-formedness locally and can add optional structural quality notices without contacting schema locations.

100% local validation
Limit: 1,000,000 characters or a 5 MB UTF-8 file
XML input
Untitled.xml Ctrl/⌘ + Enter validates · Tab inserts spaces
Validation report Not validated
</>
Your report will appear here Add XML and select Validate XML to inspect its syntax and structure.
Waiting for XML 0.0 ms
Ready. XML remains in this browser.
Elements 0
Attributes 0
Text nodes 0
Namespaces 0
Maximum depth 0
Input size 0 B
Warnings 0
Processing 0.0 ms
Validation scope: this tool checks XML well-formedness and optional structural quality conditions. It does not validate against XSD, DTD grammar, Relax NG, or Schematron rules, and it does not fetch external schema locations.
01
Private validation XML remains on your device
02
Clear diagnostics Errors include available locations
03
Defensive parsing Unsafe declarations are rejected
04
Portable reports Copy or download text and JSON
Reliable XML diagnostics

Check whether XML is well formed

This XML Validator parses XML as an XML document rather than treating it as ordinary text. It detects malformed tags, invalid nesting, unquoted attributes, incomplete documents, invalid comments, namespace issues, and other syntax that prevents successful XML parsing.

When the browser parser provides a location, the validation report includes the relevant line and column plus nearby source lines. This helps you move directly from the diagnostic to the part of the document that needs attention.

Valid documents also receive structural metrics and optional quality notices. These can identify duplicate ID-like values, unusually deep nesting, large node counts, empty elements, encoding declarations, safe document types, and schema hints.

Private and defensive browser validation

XML is processed locally. Entity declarations and external SYSTEM or PUBLIC document types are rejected before parsing to avoid unsafe, unexpectedly expensive, or external-resource behavior.

Useful validation tools

Detailed XML checks without a cluttered interface

Parse XML accurately, understand failures quickly, and export validation results for another workflow.

Native XML parsing

The browser's XML parser validates actual document structure instead of relying on fragile regular expressions.

Source context

Available parser locations are paired with configurable nearby source lines and a caret at the reported column.

Security preflight

Entity declarations and external DTD identifiers are rejected before the document reaches the parser.

Document metrics

Review element, attribute, text-node, namespace, depth, input-size, warning, and processing-time statistics.

Local XML files

Open or drag strict UTF-8 XML, XSD, SVG, RSS, or Atom files without uploading their contents.

Exportable reports

Copy a readable report or download structured results as plain text or JSON for records and debugging.

Three simple steps

How to validate XML online

Check XML syntax without installing software, creating an account, or uploading the document.

Step 1

Add your XML

Paste XML into the editor or open a strict UTF-8 document from your device.

Step 2

Validate the document

Run syntax validation and optional structural quality checks entirely inside your browser.

Step 3

Review or export

Inspect diagnostics and metrics, then copy or download the validation report as text or JSON.

Validation guidance

Best practices when checking XML

Use well-formedness validation as the first stage in a complete XML quality workflow.

1

Fix syntax before schema validation

An XSD or other schema cannot be applied reliably until the XML document is well formed.

2

Review the first parser error first

One malformed tag can create several later symptoms. Fix the earliest reported location and validate again.

3

Treat quality notices as guidance

Empty elements, missing declarations, or deep nesting may be intentional and do not automatically make XML invalid.

4

Use the correct schema tool afterward

After syntax passes, validate business rules separately with the required XSD, DTD, Relax NG, or Schematron processor.

Common questions

XML Validator FAQ

What does this XML validator check?

The validator checks whether XML is well formed, including matching elements, valid nesting, quoted attributes, legal syntax, namespace usage, comments, CDATA sections, processing instructions, and one valid root element.

Is this XML validator free?

Yes. The XML validator is free to use, requires no account, and provides syntax diagnostics, quality checks, document metrics, and downloadable reports without watermarks.

Is my XML uploaded to a server?

No. XML parsing, security preflight checks, structural analysis, and report generation happen locally inside your browser.

Does this tool validate XML against an XSD?

No. This tool validates XML well-formedness and performs structural quality checks. It does not evaluate XSD, DTD grammar, Relax NG, or Schematron rules.

Can the validator find the location of malformed XML?

When the browser parser provides location data, the validator reports the line and column and displays nearby source lines with a caret pointing to the reported column.

Why are entity declarations and external DTDs rejected?

Entity declarations and external SYSTEM or PUBLIC document types are rejected to avoid unsafe, unexpectedly expensive, or external-resource XML processing behavior.

Can I open XML files and download validation reports?

Yes. You can open or drag a strict UTF-8 XML file up to 5 MB, validate it locally, copy the report, or download the results as text or JSON.

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Ready to check your XML?

Validate XML privately with defensive parsing, clear source diagnostics, structural quality checks, useful metrics, and portable text or JSON reports.

Open XML Validator