XML - eXtensible Markup Language
What Is XML?
XML, or eXtensible Markup Language, is a flexible way to store and share structured data across different systems. Like HTML, it uses tags to describe content, but while HTML shows how data looks, XML shows what data means. In other words, XML is used to tag and sort data, while HTML is used to display that data.
XML was standardized by the World Wide Web Consortium (W3C) in 1998 to make web data more portable. At the time, developers needed a universal way to transfer information between programs written in different languages. XML became that bridge. Because it is text-based and platform-independent, XML can be read by humans and machines alike.
You’ll see XML behind many common technologies. RSS feeds use it to syndicate articles and podcasts. Microsoft Office and Google Docs use it under the hood for document formatting. Even Android apps use XML to define interface layouts. Web APIs, configuration files, and cloud storage systems (like AWS) also rely heavily on XML.
What makes XML “extensible” is its freedom. You create your own tags that describe your data:
<movie>
<title>Interstellar</title>
<director>Christopher Nolan</director>
</movie>
Unlike HTML’s fixed tags, these are completely user-defined. XML doesn’t care what the tags are called, it just ensures that the structure is consistent. It acts as a labeling system, telling programs what each piece of information is so that the program can use it.