Guide in the use of open source in the Danish public sector: The Danish authorities are focusing on ensuring flexibility and increased competition by working with open platforms and with a particular focus on infrastructure components. Via mandate from the cross governmental advisory board on architecture and standards in Denmark the focus is on how the Danish authorities can become better at using and contributing to the possibilities in relation to the reuse of software. How can we collectively contribute in terms of advice, availability, communication as well as development, quality assurance and maintenance of open source components? The initiative should be seen in light of the EU's desire to strengthen the ability to use open source within -and across member countries, which is expected to be a central element in relation to the upcoming interoperability regulation.