The rapid growth of E-Mobility has seen a significant increase in Electric Vehicle (EV) registrations and the deployment of Electric Vehicle Supply Equipment (EVSE) in Germany. Central to the future success of E-Mobility is the standardized communication between EVs and EVSE, established by the ISO 15118 standard released in 2014. Despite this, implementation of this communication varies among manufacturers, necessitating extensive interoperability testing. Traditional methods, such as Testivals, provide accurate testing but are hindered by coordination challenges and non-agile development cycles. This work proposes a solution through a virtualized runtime environment where EV and EVSE manufacturers can upload their virtualized Electronic Control Units (ECUs) and EVSE controllers for virtual ISO 15118 communication testing. This cloud-ready Software-in-the-Loop (SIL) setup enables early and parallel testing in the development process, reducing the need for physical attendance at Testivals to hardware testing only. The virtualized approach accelerates testing cycles and eliminates hardware bottlenecks, supporting the integration of a DevOps toolchain for continuous monitoring and error detection. Additionally, this thesis conducts a literature review about the utilization of SIL- and Hardwarein-the-Loop (HIL) testing to identify the boundaries and scenarios where SIL is sufficient over HIL. The virtualized runtime environment was tested against real hardware, and we concluded that while SIL testing provides realistic feedback, HIL testing is still undeniable and needed at hardware interface levels.