This presentation introduces an open co-simulation method using the Functional Mock-up Interface (FMI), a widely adopted standard supported by over 200 tools. Traditional custom API-based integrations are fragile, costly, and hard to scale, highlighting the need for standardized solutions. FMI addresses these challenges by enabling seamless model exchange and co-simulation through Functional Mock-up Units (FMUs). The session demonstrates an integration architecture using communication FMUs as a scalable, maintainable, and tool-independent solution. A practical example showcases the integration of SysML for system architecture, Modelica for physics simulation, robotics simulation, and real hardware. By leveraging FMUs from the open-source Device Driver Modelica library, this approach ensures modular, reusable, and standards-compliant communication, showcasing the transformative potential of open standards in digital engineering.