In the wake of World War I, as part of the wave of Modernism, an international functionalist architectural movement emerged, largely inspired by a desire to build a new and better world for people. Not only were buildings designed according to purpose and function, but urban planning also adopted functionalist criteria, reaching its fullest expression with the publication of the Athens Charter, the conclusions of the CIAM IV (1933), published in a revised edition by Le Corbusier in 1942. The text proposed a comprehensive reorganisation of the city based on principles of hygiene, functional rationalisation, and zoning, and it exerted a significant influence on post-war urban planning strategies.

Decades later, this approach was widely confronted with the consequences of strict urban functional separation, which undermined urban diversity. Urban well-being was no longer centred solely on hygienic concerns; diversity, safety, and heritage returned to the urban agenda as defining ideals of the postmodern city. The continuities and ruptures between the functionalist vision of the Charter of Athens and current urban agendas—particularly with regard to sustainability, mixed-use integration, and urban regeneration—have been extensively studied in recent years (Mehaffy and Haas, 2020). While the Charter of Athens promoted strict separation of urban functions and high-rise construction surrounded by green spaces, the New Urban Agenda emphasises functional diversity, connectivity between urban spaces, and citizen participation in planning.

From Le Corbusier’s didactic functionalist approach at both architectural and urban scales, postmodern architecture later disrupted the urban scene by introducing events, historical references, and provocations as critical tools to reclaim urban diversity and complexity. Patterns of public-space use and lived experience within the built environment were introduced into architectural debate in the late 1970s by Christopher Alexander and can be interpreted as early steps towards incorporating contemporary social science into urban planning, further developed through the research of Danish architect Jan Gehl. This shift can, in many respects, be read in parallel with the ideas of the American sociologist Richard Sennett, who argues that the quality of urban life is high when inhabitants are capable of engaging with complexity, and conversely poor when they are only able to relate to people like themselves.

Nowadays, with a necessary critical perspective on modern and postmodern urban models, it has become ever clearer that a new era is needed in which urban planning and architecture integrate service design and system design. Moreover, recent successful projects reveal a growing interest within the design field in considering the user as an active part of the project. Beyond participatory design, these proposals offer multiple stages at which the end user can be involved. A clear example of user inclusion at the architectural scale is the intergenerational social housing project in Esporles (Spain), designed by Emiliano López and Mónica Rivera. This residential project comprises eighteen dwellings intended for a diverse group of users, fostering social diversity and inclusion in order to create a more liveable, higher-quality environment at the close scale of everyday life.

In addition to extending the dwellings onto the common walkway through a series of benches, doors, and windows that provide varying degrees of privacy and enable spontaneous interaction between neighbours, the project fundamentally considers the user as an active element of the design at a technical level. The bioclimatic design of the building—with compact, thick load-bearing walls to the north, an inner courtyard to the south, and a porticoed structure that functions as a glazed solar collector on cold days and as a shaded open balcony during warmer periods—relies on the correct daily operation of its components. For this purpose, glazed tiles in the entrance hall display instructions guiding residents in the appropriate use of their homes.

A simple user manual—something that might appear banal at other design scales—thus becomes an innovative feature in a residential project, where participatory processes are often limited to an architectural presentation. Here, architecture is understood as a service to the user. Designing architecture at both service and system levels is becoming increasingly crucial when addressing environmental and social concerns. Printing an explanation of how the building works and how to interact with it onto glazed tiles represents an intriguing reinterpretation of the concept of the machine d’habiter, which should be considered fundamental to sustainable design. Sustainable design is ineffective without clear service and system design. How will residents interact with the building’s technical features? How can they understand the hidden technical qualities of its materials and layers? In seeking an architecture that once again relies on sustainable materials and their intrinsic characteristics—minimising the use of electronic devices to achieve a higher level of environmental responsibility—the interaction between user and built architecture becomes essential.

Taking this project as an example, its implications at the urban scale become evident. Improving the quality of public space through pedestrian areas, increasing the effectiveness of urban mobility by introducing cycling lanes, or enhancing social inclusion by integrating open-air activity areas for older people into existing urban parks must go hand in hand with the careful design of services that ensure citizen involvement and a genuinely tailored approach. This helps counter the widespread tendency for urban projects to be designed “for everyone” rather than for specific users—a tendency that often results in addressing an unreal or abstract target. Drawing on service-oriented research provides urban design with a more robust foundation and responds to the sustainability demands of contemporary urban development, in which different phases of an urban plan engage with distinct users and needs, working together to build stronger communities connected both to their urban environment and to present-day urgencies.

At the opposite end of the design scale, and in contrast to the housing project by López and Rivera, Bridgefoot Street Park in Dublin’s city centre, designed by DFLA, exemplifies the integration of contemporary urgencies into design practice. Its spatial composition incorporates construction and demolition waste in the form of secondary raw materials, addressing global challenges while laying the groundwork for aesthetic—and potentially legislative—change in approaches to waste reduction and the urban realm. The project involved the rezoning of a neighbourhood with a complex demographic profile and significant social challenges. Landscape and urban design were developed in parallel with an extensive process of community engagement, involving a genuinely diverse range of local residents. Through shared models and collaboration with community gardeners and minority groups, the project enabled tangible physical contributions to the park, resulting in a new aesthetic that reflects collective participation and a shared, evolving sensibility towards the built environment. Service design across the different phases of urban development, together with the committed involvement of developers and public authorities, emerges as a key factor in the success of relevant and meaningful interventions in the built environment.

Integrating service design at both architectural and urban scales is crucial for creating responsive, sustainable, and meaningful environments Treating users as active participants—rather than passive—enhances both functionality and social value. Service- and system-oriented approaches improve everyday usability, foster inclusive communities, and address environmental and social challenges. Designing well today requires merging technical, social, and participatory considerations into a coherent, user-centred framework that connects individual experience with collective urban life.