Shaping a Web3D Framework for Different Scientific Communities: ATON as a Service in H2IOSC

H2IOSC is a pioneering project to create a federated and inclusive cluster of research infrastructures targeting researchers from various disciplines, involved in the humanities and cultural heritage sectors with operating nodes across Italy. Within the project, several tools and services are being redesigned and/or refactored to improve accessibility for targeted communities. Among the solutions offered by E-RIHS infrastructure, the ATON framework - exposed as a service in the H2IOSC federation - was heavily refactored to accommodate the increasing demand of diverse scientific communities and their feedback for the last 10 years. With several H2IOSC pilots depending on ATON, as well as multiple national and international active projects, we discuss how the framework and its architecture evolved to quickly adapt and embrace a variety of scenarios, with a dynamic extensibility model. We report the beneficial impact H2IOSC trans-national and national (TNA/NA) calls had on driving such refactoring, based on concrete scenarios and international/national use cases. Alongside improved scalability, interoperability and mechanisms for integration with external platforms and other ecosystems, we describe plug\&play models for vertical and horizontal extensibility. We illustrate the improved plug\&play architecture for Web3D/WebXR applications, offering an accelerator to easily develop and deploy vertical applications, embracing the progressive web-application (PWA) model. We report and discuss results obtained in the last few years, including a few ongoing H2IOSC pilots and other projects adopting such models on their own instances of the framework. We also present and discuss the new ''flares'' architecture, providing a new way to extend horizontally the functionalities of the framework, able to dynamically equip web applications or extend ATON micro-service architecture. We describe a few notable cases and how flares hugely impact the overall extensibility of the framework (both client and server side). We finally present a discussion with lessons learned and how this new architecture accelerates infrastructural deployment while offering new ways to dynamically shape the operating perimeter of the service for different scientific communities.