eXtensible Markup Language
The Extensible Markup Language (XML) is a general-purpose markup language. It is classified as an extensible language because it allows its users to define their own elements. Its primary purpose is to facilitate the sharing of structured data across different information systems, particularly via the Internet. It is used both to encode documents and serialize data. In the latter context, it is comparable with other text-based serialization languages such as JSON and YAML.