XML is a markup language for documents and data interchange. It is not a programming language — it describes structure and content.
Core ideas
- Elements — nested tags like
<order><item>…</item></order> - Attributes — metadata on elements:
<item sku="A12"> - Text — character data inside elements
- Prolog — optional
<?xml version="1.0" encoding="UTF-8"?>
Going deeper
In production XML work, What is XML? matters when documents, stylesheets, or apps must stay maintainable across teams and releases—not only in isolated demos.
Common pitfalls
Watch for copy-paste configs, skipping validation or tests, and mixing concerns (structure vs presentation vs behavior) in one layer.
Practice
- Apply one technique from this lesson in the playground.
- Write one interview-style sentence explaining when you would use what is xml? on a real project.