This document defines the technical architecture of the OPTIMUM platform. The proposed technical architecture was developed based on the findings of the conceptual architecture (D1.4) and preliminary efforts related to the software components that will comprise the OPTIMUM platform. The current deliverable provides a graphical representation of the technical architecture and analytically documents the scope of each component within the platform. It also documents the identified necessary technical interfaces between the platform’s software components. It presents the OPTIMUM integrated security approach, analysing the principles behind the security strategy and emphasising the most important characteristics of the approach. In addition, it presents the OPTIMUM access policy model, which is part of the general data security approach, and which enables the dynamic modification of users’ access permissions. Last but not least, the deliverable introduces the integrated testing and evaluation strategy that will be followed in the context of OPTIMUM.