What is Extensible Markup Language (XML)

XML is a way to organize and share data using custom tags. It’s a markup language: a system that adds labels to text to show its structure and meaning, so both humans and machines can read it.

Think of XML like putting names on boxes to show what’s inside; it helps different systems understand what data is. Unlike some file types or data formats that only work with specific software, XML is flexible and works across many platforms and programming languages.

Examples

XML snippet

What it describes

<Product>

Starts the product record

<Name>Desk Lamp</Name>

The product’s name

<Price>49.99</Price>

The product’s price

<InStock>true</InStock>

Whether the product is in stock

</Product>

Ends the product record

A brief history

XML was developed by the World Wide Web Consortium (W3C) in the late 1990s as a flexible alternative to HTML (another markup language). Unlike HTML, which focuses on how information is displayed, XML focuses on describing and structuring it.

Since then, it’s become widely used in everything from ecommerce platforms and content management systems to APIs, office document formats, and data feeds.

Good to know

XML is not a programming language. It’s a way to format and organize data. You don’t need to “run” XML; instead, it’s used by software to read, import, or exchange structured content. Tools like Excel, text editors, and PIM systems can open or generate XML files. You’ll also often see it used in conjunction with XSLT (for transforming XML) or schemas (to validate structure).

Know more

Frequently Asked Questions

How is XML different from HTML?
Both XML and HTML are markup languages, but they have different purposes: XML is used to describe data, while HTML is used to display it. XML is also customizable and doesn’t have predefined tags.
How is XML different from JSON?
Although the developer of JSON declared that it is not a markup language, it is now often treated as one. Both XML and JSON store structured data, but JSON is typically shorter and easier to read. XML supports features like attributes and schemas, which make it useful in more complex applications.
Do I need to learn XML to use it?
You don’t necessarily need to learn XML to use it. Many systems create and handle XML for you. But understanding the basics can help when troubleshooting or integrating systems.