XML (eXtensible Markup Language) is a markup language for encoding documents in a format that is both human-readable and machine-readable. It's used for data exchange, configuration files, and document storage. For web APIs, many developers now prefer JSON as a lighter-weight alternative.
What makes XML valid?
Valid XML must have a single root element, properly nested and closed tags, quoted attribute values, and case-sensitive matching tags. The validator checks all these rules.
What's the difference between XML and HTML?
XML is strict about syntax (all tags must close, attributes must be quoted), while HTML is more forgiving. XML is for data, HTML is for display. Check our HTML Validator for HTML files.
Where is my XML processed when I validate it?
Entirely inside your browser. The XML you paste is parsed and validated locally with JavaScript, so SOAP payloads, RSS feeds, or configuration documents are never uploaded. The tool also works offline once the page has loaded.
