aid: xml
name: XML
description: >-
  XML (Extensible Markup Language) is a W3C standard markup language and data format that
  defines rules for encoding documents in a way that is both human-readable and machine-readable.
  Originally published as a W3C Recommendation in 1998 (XML 1.0), XML provides the foundation
  for a wide ecosystem of related standards including XML Schema, XSLT, XPath, XQuery, SOAP,
  XHTML, SVG, RSS, Atom, and many domain-specific vocabularies. XML remains a core data
  interchange format for enterprise systems, web services, configuration, and document publishing.
type: Index
url: https://www.w3.org/XML/
tags:
  - Data Formats
  - Document
  - Markup Language
  - Standard
  - W3C
  - Web Services
  - XML
created: '2025'
modified: '2026-05-03'
specificationVersion: '0.19'
apis:
  - aid: xml:xml-10
    name: XML 1.0
    description: >-
      Extensible Markup Language (XML) 1.0 is the foundational W3C Recommendation defining
      the syntax and processing model for XML documents. First published in 1998 and now in
      its Fifth Edition (2008), XML 1.0 specifies well-formedness, validity, character encoding,
      and the basic constructs (elements, attributes, namespaces, processing instructions,
      comments, and entities) that all XML technologies build upon.
    humanURL: https://www.w3.org/TR/xml/
    tags:
      - Document
      - Markup Language
      - Standard
      - W3C
      - XML
    properties:
      - type: Documentation
        url: https://www.w3.org/TR/xml/
      - type: Specification
        url: https://www.w3.org/TR/xml/
  - aid: xml:xml-11
    name: XML 1.1
    description: >-
      Extensible Markup Language (XML) 1.1 is a W3C Recommendation published in 2006 that
      extends XML 1.0 to support newer Unicode versions, additional line ending characters,
      and a broader set of name characters. XML 1.1 is rarely deployed in practice; XML 1.0
      remains the dominant version used in production systems.
    humanURL: https://www.w3.org/TR/xml11/
    tags:
      - Document
      - Markup Language
      - Standard
      - W3C
      - XML
    properties:
      - type: Documentation
        url: https://www.w3.org/TR/xml11/
      - type: Specification
        url: https://www.w3.org/TR/xml11/
  - aid: xml:xml-namespaces
    name: XML Namespaces
    description: >-
      Namespaces in XML 1.0 (Third Edition) is the W3C Recommendation that defines a mechanism
      for qualifying element and attribute names in XML documents using URI references. XML
      Namespaces allow vocabularies from different sources to be combined in a single document
      without naming collisions, and underpin every modern XML application including XHTML,
      SOAP, XSLT, and SVG.
    humanURL: https://www.w3.org/TR/xml-names/
    tags:
      - Namespaces
      - Standard
      - W3C
      - XML
    properties:
      - type: Documentation
        url: https://www.w3.org/TR/xml-names/
      - type: Specification
        url: https://www.w3.org/TR/xml-names/
  - aid: xml:xml-schema
    name: XML Schema (XSD)
    description: >-
      XML Schema Definition Language (XSD) is the W3C Recommendation for describing the
      structure and constraints of XML documents using an XML-based grammar. XSD 1.1 is the
      current version and provides element/attribute declarations, complex and simple types,
      keys/keyrefs, assertions, and conditional type assignment.
    humanURL: https://www.w3.org/XML/Schema
    tags:
      - Schema
      - Standard
      - Validation
      - W3C
      - XML
    properties:
      - type: Documentation
        url: https://www.w3.org/XML/Schema
      - type: Specification
        url: https://www.w3.org/TR/xmlschema11-1/
common:
  - type: Website
    url: https://www.w3.org/XML/
  - type: Documentation
    url: https://www.w3.org/TR/xml/
  - type: Specification
    url: https://www.w3.org/TR/xml/
  - type: GitHub Organization
    url: https://github.com/w3c
  - type: GitHub Repository
    url: https://github.com/w3c/xml
  - type: JSONSchema
    url: >-
      https://raw.githubusercontent.com/api-evangelist/xml/refs/heads/main/json-schema/xml-document-schema.json
  - type: JSONSchema
    url: >-
      https://raw.githubusercontent.com/api-evangelist/xml/refs/heads/main/json-schema/xml-element-schema.json
  - type: JSONStructure
    url: >-
      https://raw.githubusercontent.com/api-evangelist/xml/refs/heads/main/json-structure/xml-document-structure.json
  - type: JSONLDContext
    url: >-
      https://raw.githubusercontent.com/api-evangelist/xml/refs/heads/main/json-ld/xml-context.jsonld
  - type: Vocabulary
    url: >-
      https://raw.githubusercontent.com/api-evangelist/xml/refs/heads/main/vocabulary/xml-vocabulary.yml
maintainers:
  - FN: Kin Lane
    email: kin@apievangelist.com