XML Validator

Validate XML and instantly detect syntax errors with line-level hints before using XML in APIs, feeds, or config workflows.

What this tool does

This tool validates XML syntax so you can catch malformed tags, invalid nesting, and broken attributes before XML reaches downstream systems. It is useful for API payloads, RSS/Atom feeds, and configuration files where parse failures can break processing. You can optionally format valid XML during validation to improve readability while debugging. It checks syntax and structure, not XSD schema rules.

Tool interface

Validate XML input

Check XML syntax, identify parse errors quickly, and optionally format valid XML before downstream use.

If your XML is valid, continue with the XML to JSON Converter for downstream mapping or exports.

Open XML to JSON Converter

Example input

Valid XML example:
<users>
  <user id="1">
    <name>Ana</name>
  </user>
</users>

Invalid XML example:
<users>
  <user id="1">
    <name>Ana</name>
</users>

Example output

Valid result:
Valid XML. No syntax errors found.

Invalid result:
XML validation failed
Mismatched closing tag near line 5 (exact parser message may vary).

Step-by-step instructions

  1. Paste XML into the input field or upload an XML file.
  2. Optionally enable format before validate if you want normalized indentation.
  3. Click Validate XML to run syntax checks.
  4. If invalid, review the highlighted parser error and line hint.
  5. Fix the issue and run validation again until the document is valid.

Common use cases

  • Validating XML API responses before mapping fields in integration code.
  • Checking RSS, Atom, or product feed XML before publishing updates.
  • Debugging XML configuration files used by legacy systems.
  • Catching malformed XML payloads during QA and regression testing.

Catch XML syntax issues early so API integrations, feed imports, and config parsing do not fail in production.

Common mistakes to avoid

  • Missing closing tags. Invalid: `<user><name>Ana</name>` Fix: `<user><name>Ana</name></user>`.
  • Closing tags out of order (invalid nesting). Invalid: `<a><b></a></b>` Fix: `<a><b></b></a>`.
  • Leaving attributes unquoted. Invalid: `<user id=1>` Fix: `<user id="1">`.
  • Expecting this syntax check to validate XSD schema rules.
  • Pasting fragments with multiple roots. Invalid: `<a></a><b></b>` Fix: wrap under one root element.

Frequently Asked Questions

How do I validate XML online with this tool?

Paste XML or upload a file, then click Validate XML. The tool parses the document and reports syntax errors immediately.

What makes XML invalid?

Common causes are missing closing tags, invalid nesting order, unquoted attributes, duplicate attributes, and malformed entities.

Can this XML validator show the error line number?

Yes. When parser line information is available, the tool displays line and column hints with the error message.

Does this validator check XML schemas (XSD)?

No. It validates XML syntax and structure, not XSD schema constraints.

Can I validate large XML files?

Yes for typical browser-sized files. Very large files may be slower depending on your device and browser memory limits.

Can I format XML before validation?

Yes. Enable format before validate to normalize indentation when the XML parses successfully.

Does this tool store my XML data?

No. Validation runs in your browser.

Can I validate XML from API responses and feeds?

Yes. Paste raw XML from API payloads, RSS/Atom feeds, or config files to check syntax quickly.

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