AWS has launched Lambda MicroVMs, a new serverless compute primitive that runs each user session or AI agent in its own Firecracker virtual machine. Unlike Lambda Functions, MicroVMs provide hardware-level VM isolation, snapshot-based rapid launch, and stateful execution with suspend/resume lifecycle for up to eight hours. Each MicroVM gets up to 16 vCPUs, 32 GB RAM, and 32 GB disk, and is available in five regions on ARM64. The service targets multi-tenant applications that need to execute untrusted or AI-generated code safely — a gap that containers (shared kernel) and traditional VMs (slow cold start) couldn't fill simultaneously. Compared to Cloudflare Sandboxes, GKE Agent Sandbox, and Azure Container Apps dynamic sessions, AWS's approach emphasizes stateful isolation with suspend/resume. A Reddit analysis flagged the cost premium: the minimum setup runs ~$3.03/day, roughly 9x Fargate spot pricing.
