Definition:
XML, which stands for“Extensible Markup Language“, is a markup language that defines a set of rules for encoding documents in a human-readable and machine-readable format. It is defined by the W3C XML 1.0 specification and several other related specifications, which are open and free standards. The design goals of XML emphasize simplicity, generality and ease of use on the Internet.
Although originally designed for documents, XML is widely used to represent arbitrary data structures, such as those used in web services. Several schema systems exist for defining XML-based languages, and many application programming interfaces(APIs) have been developed to facilitate the handling of XML data.
XML Applications
Since 2009, hundreds of document formats have been developed using XML syntax, including RSS, Atom, SOAP and XHTML. XML-based formats have become the default standard for many office tools, such as Microsoft Office (Office Open XML), OpenOffice.org and LibreOffice (OpenDocument), and Apple’s iWork.
XML is also used as the base language for communication protocols, such as XMPP. Applications for the Microsoft .NET Framework use XML files for configuration, and Apple has implemented an XML-based logging system.
Data exchange and XML
XML has become a common standard for exchanging data over the Internet. IETF RFC 7303 establishes the rules for constructing Internet media types for sending XML. It also defines the media types application/xml and text/xml, which indicate that the data is in XML format, without specifying its semantics. However, the use of text/xml has been criticized due to potential encoding problems and it is suggested that it be considered obsolete. RFC 7303 also recommends that XML-based languages end in +xml, such as image/svg+xml for SVG.
Recommendations for the use of XML
RFC 3470, also known as IETF BCP 70, provides guidelines for the use of XML in a network context. This document covers many aspects of the design and deployment of an XML-based language, ensuring that it is used efficiently and effectively in different applications and network environments.