Invalid XML Element Name – Fix Start Tag Name Errors

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XML element names must follow XML name syntax and cannot begin with characters such as ordinary digits.

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XML name syntax

How to fix an invalid XML element name

The sample starts the element name with the digit 1. XML names have stricter lexical rules than arbitrary object keys or database column names, so data mapped into element names may need a deliberate naming scheme. This tool is free to use. No account or payment is required.

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What you can do here

  • XML well-formedness validation
  • Broken XML example preloaded
  • Corrected XML comparison
  • .xml file import
  • Browser parser feedback
  • Browser-local processing

Steps

  1. Find the element name at the parser error and check its leading character.
  2. Rename generated numeric or otherwise invalid keys to a stable XML-safe element name.
  3. Update the matching closing tag and validate the whole document again.

JSON keys do not automatically make valid XML tag names

A key such as 1root is legal in JSON when quoted, but cannot be copied directly into an XML element name. Converters need an explicit mapping instead of assuming every source key is a valid XML name.

Keep renamed start and end tags synchronized

After changing an element name, make the same change to its closing tag. Otherwise the original name error may be replaced by a mismatched-tag error.

Invalid XML element name example

Move the numeric suffix away from the first character of the element name.

Invalid XML

<1root>value</1root>

Corrected XML

<root1>value</root1>

Common questions

Frequently asked questions

Can an XML element name start with a number?

No. Ordinary XML names cannot start with a digit.

Are XML element names case-sensitive?

Yes. The same case must also be used by the corresponding closing tag.

Why can a valid JSON key fail as an XML element name?

JSON object keys are strings, while XML element names follow XML-specific lexical rules.

Recommended next steps

Undeclared XML Namespace PrefixDeclare namespace prefixes before using prefixed element or attribute names.XML Mismatched TagFind opening and closing element names that do not match.XML Validator Online – Check XML SyntaxPaste any XML document and check well-formedness locally in your browser.

Debugging a specific XML issue? Browse XML troubleshooting.