Reactor adds NVIDIA and Sapphire backing, taking total funding to $74M for real-time world-model inference infrastructure

What changed

Reactor announced on October 5 that NVIDIA's NVentures and Sapphire Ventures had joined its Series A, bringing total funding to $74 million. Reactor does not train a world model of its own; it provides real-time inference, GPU cloud, streaming, SDK and API infrastructure for interactive generative video and world-model workloads. Sapphire says these sessions require stateful, bidirectional serving under roughly 50 milliseconds, and names Overworld, Visko.ai and Moonlake.ai as production customers, with compute deployments across the US, Europe, Japan and Korea via AWS and Nebius.