The document summarizes Spain's efforts to promote interoperability of public sector information through open data strategies and standards. Key elements include Royal Decree 1495/2011, which established a standard open data license and required all public sector information be reusable. Interoperability guidelines specify how to select, identify, describe, format, publish and catalog public sector datasets using standards like DCAT to ensure interoperability across systems. The guidelines comprise Spain's national interoperability framework for eGovernment strategies under Ley 11/2007.