Well-formed XML versus schema-valid XML
A parser can confirm that XML has a coherent document structure, but only a schema or application-specific validator can check whether the content is allowed.
Use well-formedness checks to catch missing end…
Use well-formedness checks to catch missing end tags, malformed nesting, and invalid syntax during a first review.
Check the target schema separately when element…
Check the target schema separately when element names, attributes, namespaces, value formats, or required order matter.
Treat external entities, sensitive configuration, and large…
Treat external entities, sensitive configuration, and large production documents with an approved local or controlled validation workflow.
Use the related tool carefully
This guide is paired with a browser-only utility. The tool is a practical aid for small examples and inspection; it is not a substitute for application testing, a formal data pipeline, or professional review where the decision has higher consequences.
Open the related XML Formatter and Validator