THE PRACTICAL GUIDE · NORMANDIN SYSTEMS
Get more from XML Linter
XML Linter helps you check syntax in XML. An XML syntax check helps detect mismatched tags, malformed attributes, and structural issues before another application reads the document. This is useful when the information is already available but its structure, presentation, or consistency makes it difficult to inspect. Work with a representative sample first so that you can recognize the expected result before applying the same operation to a larger document. Well-formed XML is not necessarily valid against a schema or DTD. Namespace correctness can also involve application requirements beyond syntax. Keep the original input available while reviewing the output. The important check is whether the result still has the intended values and relationships, rather than whether it merely looks neater. Check the first reported error before later errors, which may be consequences of the same malformed tag.
Guide updated October 13, 2026
How to use this tool
- Place the XML input in the relevant editor. If the tool compares or combines documents, keep each document in its own input.
- Select the available settings for the operation you need. Check the first reported error before later errors, which may be consequences of the same malformed tag.
- Review any syntax errors before interpreting the result. A valid document with the wrong structure needs a different fix from malformed input.
- Inspect the changed portion and at least one unchanged portion. Keep a copy of the original XML until the result has been checked in its destination.
SEE IT IN PRACTICE
A worked example
<root><name>Ada</root>
A mismatched or unclosed name element
The name start tag needs a matching end tag before root closes. Balanced nesting is part of well-formed XML.
Well-formed is only the first layer
An XML parser checks balanced nesting, attribute syntax, and document structure. A schema adds constraints such as required elements and allowed value types. An application may impose additional business rules. Investigate the earliest syntax error first, since one unclosed quote can make many later lines appear broken. After syntax is fixed, validate against the actual consuming system.
Element names and attribute syntax
Every non-empty start tag needs a matching end tag with proper nesting. Attribute values need delimiters, and reserved characters in text or attributes need the appropriate escaping. A single malformed attribute can make the rest of the document appear broken. Fix the earliest issue, then run the check again. Passing this syntax stage does not establish that the element names, namespaces, or values satisfy an application’s schema.
When this tool is useful
- Review XML import data while keeping the underlying structure visible.
- Reproduce parser error locations with a compact, reproducible sample.
- Check markup after a manual edit before copying data into another application.
Tips for a better result
- Well-formed XML is not necessarily valid against a schema or DTD. Namespace correctness can also involve application requirements beyond syntax.
- Check the first reported error before later errors, which may be consequences of the same malformed tag.
- Use a small XML example to isolate an unexpected result. Add nested objects, arrays, quoted text, and empty values only as needed to reproduce the behavior.
Frequently asked questions
Does this establish that my XML is correct?
It checks or transforms the aspects covered by this operation. It cannot establish whether the values match your business rules, whether required records are missing, or whether the receiving application accepts the same structure.
Why do visually similar inputs behave differently?
Value types, nesting, array order, duplicate names, and invisible whitespace inside strings can carry meaning. Compare the parsed structure and exact values, rather than judging only the way the document appears on screen.
What is a useful review process?
First resolve syntax errors, then inspect the specific result this tool produces. Check the first reported error before later errors, which may be consequences of the same malformed tag. Finally, test a representative result with the application that will consume it.
What happens to the information I enter?
The utility processes your input in this browser. Some tools retain field values in browser storage or the URL; avoid entering secrets in shareable fields. Page and asset requests still go to the hosting provider. Read the privacy and offline-use notes for details.