The circular economy paradigm establishes clear objectives for product recovery, reuse, and recycling, advocating for the design of goods capable of sustaining multiple lifecycles. As industries shift from linear to circular models, interorganizational synergies become essential to enable efficient waste exchange, optimize remanufacturing, and foster industrial symbiosis. The proliferation of circular ecosystems (CEs) across Europe underscores the need for strategic digital tools that facilitate collaborative, closed-loop value chains. In this context, mass customization (MC) emerges as a promising yet underexplored enabler of circular economy implementation. By promoting adaptable product design and modularity, MC can significantly contribute to extending product lifespans and enhancing reuse potential. This study investigates the intersection between MC strategies and collective closed-loop systems, focusing on the role of digital toolkits for product customization, known in the literature as product configurators. Originally developed to support product personalization, configurators are examined for their potential to enable product and component reconfiguration, thereby supporting component recovery and waste management within CE platforms. To achieve these target outcomes, the present study aims to map the current digital CE landscape to evaluate the potential of configurators as tools for circular strategies through improved system interoperability, user engagement, and lifecycle intelligence. Empirically, the research analyzes a representative sample of European CE platforms to assess how configurators might impact technological infrastructures and collaborative practices. The study identifies actionable visions for both researchers and practitioners interested in leveraging digital tools to scale up circular innovation and interfirm collaboration.