Towards the Model-Based Engineering of Composable and Reusable Digital Twins: the Digital Twin Interface Concept

Abstract

Digital Twins (DTs) are increasingly adopted to support the monitoring, simulation, and optimization of large and complex systems. As DT ecosystems expand, enabling reuse, modularity, and federation across heterogeneous DTs becomes a critical challenge. Multiple initiatives already focused on modeling DT constituents such as gateways, data, models, and services. However, more limited attention has been devoted to systematically engineering the interfaces that enable DT composition and interoperability. This vision paper introduces the concept of the Digital Twin Interface (DTI) as a first-class, model-based abstraction to support both design-time (static reuse) and runtime (dynamic interaction) integration scenarios. We propose a multi-faceted classification covering gateway, model, data, and service interfaces. At the same time, we explicitly distinguish between provided and required interfaces. Based on our proposal, we discuss key enablers, supporting standards, and related open challenges for the Model-Based Engineering (MBE) community. We argue that explicit DT interfaces are foundational for building composable, reusable, and federated DT ecosystems.