Flex Reservations and Spot Explained | CoreWeave Blog

What this post added

This post introduces and explains two new capacity models: Flex Reservations and Spot instances. Flex Reservations are detailed as a system that separates guaranteed access from continuous run-rate pricing, featuring a lower holding fee for reserved capacity and a complementary usage rate applied only when nodes are in use. Spot instances are described as lower-cost compute for interruptible workloads, with a focus on CoreWeave's differentiated approach to preemption signaling, providing explicit termination signals and a defined notice window. The post also outlines use cases and best practices for each model, including integration with CoreWeave ARENA for testing Spot instances.