Formex V4 describes the format for the exchange of data between the Publication Office and its contractors. In particular, it defines the logical markup for documents which are published in the different series of the Offical Journal of the European Union. Formex V4 supports also the document types of CASELAW (jurisprudence), CONSLEG (consolidated legislation) and LSEU (legislative summaries).
Formex V4 is based on the international standard format XML (Extensible Markup Language — W3C Recommendation, February 10, 1998). It entered into force on May 1st, 2004. The documentation only exists in English.