Zeroboot: Sub-Millisecond VM Sandboxes via Copy-on-Write Memory Forking — 83pts HN

GitHub·medium signal

Zeroboot uses Firecracker + CoW mmap forking to spawn KVM-isolated VM sandboxes in 0.79ms p50 (1.74ms p99) with 265KB memory per instance — vs. E2B's ~150ms and ~128MB. The technique boots a template VM once, captures a memory snapshot, then forks it for each agent execution request. At this scale, sandboxed code execution becomes viable inside interactive agent loops where latency directly impacts UX.