CEN MetaLex

Open XML Interchange Format for Legal and Legislative Resources


CEN MetaLex standardizes the way in which sources of law and references to sources of law are to be represented in XML. It was developed by the CEN Workshop on an Open XML Interchange Format for Legal and Legislative Resources (MetaLex).

What Does it Do?

  • MetaLex enables public administrations to link legal information from various levels of authority and different countries and languages.
  • MetaLex enables companies that are active in the field of legal knowledge systems to connect to and use legal content in their applications, which allows them to support a much larger market.
  • An open interchange protects customers of such companies from vendor lock in
  • Finally, the standard helps to improve transparency and accessibility of legal content for citizens and businesses.

CEN MetaLex is an interchange format, a lowest common denominator for other standards, intended not to replace jurisdiction-specific standards and vendor-specific formats in the publications process but to impose a standardized view on legal documents for the purposes of information exchange and interoperability in the context of software development.

To meet these requirements, MetaLex defines a mechanism for schema extension, adding metadata, cross referencing, constructing compound documents and a basic naming convention.

What does it look like?

The MetaLex Document Server hosts several thousands of regulations as CEN MetaLex documents that were converted from the Dutch wetten.overheid.nl portal. For instance, the Rome Statute of the International Criminal Court. You can also browse its metadata.

MetaLex in the Wild

UK Legislation

The website www.legislation.gov.uk brings together legislation from across the UK in one place. The site contains legislation as it is originally enacted or made with the revised versions of Acts of Parliament, showing changes to legislation over time. Underneath the hood of the website is a native XML database and an API which supports content negotiation. The collection distinguishes the bibliographic identifiers identified by the CEN MetaLex recommendation:

Dutch Legislation

The website doc.metalex.eu (the MetaLex Document Server) publishes all Dutch regulations as CEN MetaLex and RDF Linked Data.


Workshop Agreement (2010)

XML Schema

OWL Ontology

Document Server

Additional Material

Slides on MetaLex at Slideshare

Papers on MetaLex at Google Scholar


The namespace of the XML Schema and OWL Ontology is:


We support content negotiation on this URI. Depending on the client used to access it, the server either returns the latest workshop agreement, the XML Schema, or the OWL specification.


The CEN workshop on an Open XML interchange format for legal and legislative resources officially started on July 7 2006. The objective of the Workshop was to develop a CEN Workshop Agreement (CWA) on an Open XML interchange format for legal and legislative resources; The CWA was accepted by the CEN and associated standard organisations as a publicly available specification (PAS or pre-norm) for the period of three years, after which the agreement must be renewed or upgraded to a norm.

CEN has a web page dedicated to the workshop. You can use this page to register for the workshop and download the business plan of the workshop.


Technical Committee