The ECHELON software has been developed by SRT since 2012 and in joint partnership with Eni since 2018. It is a full-featured and robust code, thoroughly tested and deployed on critical business assets by our clients and industry partners. It incorporates rigorous and well-documented governing equations, discretization schemes, and convergence criteria and adheres to results produced by industry-reference legacy simulators. ECHELON runs on one or multiple GPUs which can be in a laptop, workstation, server, on-premise cluster, or cloud and is available under Windows and Linux. It runs black oil and compositional models, and offers complex field management, reservoir coupling, integrated surface networks, EOR, and much more. Its key differentiators over competing simulators are its unparalleled performance, exceptional scalability, reduced hardware requirements and lower total cost of operation.