Why XML?

XML, the Extensible Markup Language, is derived from SGML, the Standard Generalized Markup Language. SGML has been a cornerstone of document management systems for decades. As a simplified subset of SGML, XML inherits its robustness and flexibility, making it a mature choice for data representation and interchange.

The Specific Case for XML

In the Intellectual Property (IP) domain, XML has long been the established means of information exchange. Standards like WIPO’s ST.96 are actively maintained, developed, and widely used by many parties within the IP space.

Relevance for the IPI datadelivery API:

  • The API service produces XML results conforming to the ST.96 standard whenever possible.

  • Clients must process XML responses, so it is natural to maintain consistency by using XML to represent request details as well. This is particularly beneficial for requests with significant inherent complexity, such as unambiguously representing sophisticated nested queries combined with logical predicates (AND/OR/NOT).

  • Additionally, the API allows for request input validation by both the API service and the clients before processing. This ensures data integrity and reduces the likelihood of errors during data interchange.

The General Case for XML

XML has been in use since its standardization in 1998, providing over two decades of service in various technological domains. Its longevity has resulted in a rich set of mature tools and technologies, making it a battle-tested choice for enterprise-level applications. While alternative formats like JSON have grown in popularity due to their perceived simplicity and reduced verbosity, XML offers several benefits:

  • Extensibility: XML’s design allows for the composition of different schemas. This enables a single document to seamlessly incorporate elements from various XML vocabularies, facilitating a modular and flexible design approach. XML supports the merging of schemas via namespaces, a feature essential for complex data representations involving multiple domains. This allows the integration of new data types without disrupting existing structures.

  • Comprehensive Support Across Platforms: XML is widely supported by major programming languages like Java, .NET, and Python, offering robust libraries and APIs for efficient processing. Its universal format ensures interoperability and cross-platform compatibility, adhering to W3C standards. Additionally, extensive community resources and documentation provide strong support for developers.

  • Tooling Maturity: A wide range of robust tools for editing, validating, and transforming XML data exists. Editors like Oxygen XML Editor offer advanced functionalities, including schema validation and integrated XSLT processing.

  • Standards and Schemas: The XML ecosystem supports numerous standards, such as XSD (XML Schema Definition) for schema definitions, which provide rigorous data typing and validation functionalities. This offers a level of precision in defining structured data that JSON Schema is still evolving to match.

  • Transformation Technologies: XSLT (eXtensible Stylesheet Language Transformations) enables powerful transformations of XML data, facilitating complex data manipulation, presentation, and interoperability between diverse systems.

  • XML Catalogs: XML catalogs provide a way to manage and resolve multiple namespaces and schema locations, a critical feature in large-scale systems where many interoperating schemas are used.

Despite its strengths, XML has faced criticism and several myths have emerged. Here are some common misconceptions and clarifications:

  • Myth: XML is overly verbose and cumbersome.
    Fact: While XML can be more verbose compared to JSON, its verbosity is a byproduct of its design goals, which include readability, explicit structure, and self-description. In many enterprise applications, the benefits of a self-describing and well-validated format far outweigh the increased document size.

  • Myth: XML is obsolete in the modern development landscape.
    Fact: XML continues to thrive in domains where strict validation, data integrity, and robust data transformations are key. Many industries, including finance, healthcare, and legal documentation, rely on XML for data interchange due to its maturity and reliability.

  • Myth: JSON is always a better choice.
    Fact: JSON is indeed simpler and better suited for scenarios where lightweight data transfer is required. However, in contexts that demand strict adherence to standards, complex data structuring, and extensive tool support, XML remains unmatched.