This document describes the core concepts, architectural design and guidelines for the development of the INFINITY Web Repository, an on-‐line catalogue of Future Internet infrastructures. The INFINITY Web Repository, through innovative community-‐driven Web tools, will describe infrastructures as a 'living organism', and bring together the two key aspects of FI-‐PPP projects: the infrastructures and the applications. In Section 1 we provide an overview of the scope of the deliverable and of the procedure of maintenance of the design documentation of the INFINITY Web Repository. This also section includes guidelines for readers. Section 2 provides a survey of existing Web applications that may provide inspiration for INFINITY Web Repository and an analysis of Web development frameworks that can be adopted for its development. Section 3 offers a high-‐level description of the Web Repository, its expected features and requirements. In Section 4 we describe the architecture of the repository and its design principles. This section focuses in particular on features that are expected to be available in the first release of the repository, while the features identified for the second release are addressed to a lesser degree. Their design will be discussed in the updated version of this document that will be released at month 14. Section 5 presents a wireframe realized to study the repository design and to collect feedbacks from FI-‐PPP projects. Section 6 and 7 provide important references for the developers. Section 8 summarizes the content of the deliverable and the next steps for the activities of Work Package 4.