What is Interoperability Architecture

New legal settings, the need for improved quality of service, and technological advances increase the pressure on public administrations to cooperate in order to modernize and innovate procedures. Thus, the automation of cross-organisational processes is a clear objective. But due to the traditional independence of administrations, as well as the need to minimize modifications of internal systems, a loose coupling rather than tight system integration is desired. In this vein, a method is required that enables public administrations to create comprehensive interfaces they can publish to collaboration partners. This chapter presents the concept for a Business Interoperability Interface that describes the externally visible behaviour of administrations and supports the design and execution of loosely coupled, cross-organisational processes. Requirements for this interface are derived from the Europol-Eurojust collaboration, and the development and application of the Business Interoperability Interface are illustrated with the same scenario.