XML
Markup for arbitrary structured data.
💡
This course has 3 lessons. Start with the first one and use the next / previous links at the bottom of each lesson — the sidebar keeps the whole course in order.
Lessons
- XML syntax and well-formednessElements, attributes, entities and CDATA, plus the exact rules a document must satisfy to be well-formed.
- NamespacesHow URIs disambiguate element names, how default and prefixed namespaces differ, and the attribute trap that breaks XPath queries.
- Validation with DTD and XSDWhat DTDs and XSDs can express, how to write a usable schema, and when XML is still the right choice today.
More in XML & Web Services
XPath XSLT SOAP RESTful APIs RSS & Atom
Last refreshed 2026-09-17.