This is the home page of the TOOP Reference Architecture wiki. It includes documentation about the TOOP Reference Architecture (TOOPRA) and is related with the WP2 deliverable D2.4.

The TOOP Solution Architecture wiki includes documentation about the TOOP Solution Architecture (TOOPSA), the software components and the domain specific profiles and implementations and is related with the WP3 deliverable D3.3.

The TOOP Pilots wiki includes documentation about the TOOP Pilots and is related with the WP3 deliverables D3.1 and D3.2.

The Once-Only Principle (OOP) states that information  should be registered once and reused whenever needed. It is one of the pillars of the strategy for the Digital Single Market and one of the basic principles of the EU eGovernment Action Plan 2016-2020, which requires that the public administrations should ensure that citizens and business supply the same information only once to public administration”.

The goal of the Once-Only Principle Project (TOOP) Reference Architecture (TOOPRA) is to assist organisations in the cross-border implementation of the OOP.

A Reference Architecture is a set of standardized architectures that provides a frame of reference for a particular domain, sector or field of interest (Proper and Lankhorst 2014). The TOOPRA is concerned with the implementation of the OOP.

Although focused on the cross-border implementation, the reference architecture is generic and it can for most parts also be applied in a national context. It can also be profiled acoording to different application domains.

The reference architecture is described on all four architecture layers (business, data, application, technology), organized in multiple views according to TOGAF Framework (The Open Group 2005-2018): 

  • Business Architecture: a representation of business concerns through capabilities, end-to-end value delivery, information, and organizational structure; and the relationships among these business elements; 
  • Information System Architecture includes the data and application architecture, and describes (1) the structure of an organization's logical and physical data assets and data management resources, and (2) the individual application systems to be deployed, their interactions, and their relationships to the core business processes of the organization; 
  • Technology Architecture "describes the logical software and hardware capabilities that are required to support the deployment of business, data, and application services. This includes IT infrastructure, middleware, networks, communications, processing, standards, etc".

It is complemented with specific views addressing cross-cutting quality concerns, such as:

The Architecture Drivers and Decisions component of TOOPRA presents the Stakeholders, Architecture Principles (AP), Architecturally Significant Requirements (ASRs), Architecture Gaps, and Architecture Requirements Mapping, together with comparison of TOOPRA and the TOOP Solution Architecture. In particular, the Stakeholders section provides the goal model of TOOPRA, its target users and use cases, as well as main stakeholders. 

The Semantic View section describes the OOP Semantic Model, the Core vocabularies and Application Profiles, and the methodology for modelling Domain Semantic Models (DSM) in the context of Once-Only Principle.

The architecture profiling section provides examples of three main profiles based on the TOOP pilots.

The final deliverable D2.4 is comprised of the textual component and the current wiki component. Most technical level diagrams of TOOP Reference Architecture use the  default iconography of the ArchiMate language [1].  



Proper, Henderik A., and Marc M. Lankhorst. 2014. “Enterprise Architecture. Towards Essential Sensemaking.” Enterprise Modelling and Information Systems Architectures 9 (1):5–21.

The Open Group. “TOGAF®, an Open Group Standard” 2005-2018.

  • No labels