Zeroboot VM Sandbox Skill by [ara.so](https://ara.so) — Daily 2026 Skills collection. Zeroboot provides sub millisecond KVM virtual machine sandboxes for AI agents using copy on write forking. Each sandbox is a real hardware isolated VM (via Firecracker + KVM), not a container. A template VM is snapshotted once, then forked in ~0.8ms per execution using mmap(MAP PRIVATE) CoW semantics. How It Works 1. Template : Firecracker boots once, pre loads your runtime, snapshots memory + CPU state 2. Fork (~0.8ms) : New KVM VM maps snapshot memory as CoW, restores CPU state 3. Isolation : Each fork is a separate KVM VM with hardware enforced memory isolation Installation Python SDK Node/TypeScript SDK Authentication Set your API key as an environment variable: Never hardcode keys in source files. Quick Start REST API (cURL) Python TypeScript / Node.js Common Patterns AI Agent Code Execution Loop (Python) Concurrent Sandbox Execution (Python) TypeScript: Agent Tool Integration REST API with fetch (TypeScript) Health Check API Reference POST /v1/exec Execute code in a fresh sandbox fork. Request: Headers: Response: Performance Characteristics Metric Value Spawn latency p50 ~0.79ms Spawn latency p99 ~1.74ms Memory per sandbox ~265KB Fork + exec Python ~8ms 1000 concurrent forks ~815ms Each sandbox is a real KVM VM — not a container or process jail Memory isolation is hardware enforced (not software) CoW means only pages written by your code consume extra RAM Self Hosting / Deployment See [docs/DEPLOYMENT.md](docs/DEPLOYMENT.md) in the repo. Requirements: Linux host with KVM support ( /dev/kvm accessible) Firecracker binary Rust 2021 edition toolchain Architecture Notes Snapshot layer : Firecracker VM boots once per runtime template, memory + vCPU state saved to disk Fork layer (Rust): mmap(MAP PRIVATE) on snapshot file → kernel handles CoW page faults per VM Isolation : Each fork has its own KVM VM file descriptors, vCPU, and page table — fully hardware separated No shared kernel : Unlike containers, each sandbox runs its own kernel instance Troubleshooting /dev/kvm not found (self hosted) API returns 401 Unauthorized Verify ZEROBOOT API KEY is set and starts with zb live Check the key is not expired in your dashboard Timeout on execution Default execution timeout is enforced server side Break large computations into smaller chunks Avoid infinite loops or blocking I/O in sandbox code High memory usage (self hosted) Each VM fork starts at ~265KB CoW overhead Pages are allocated on write — memory grows with sandbox activity Tune concurrent fork limits based on available RAM Resources [API Reference](https://github.com/adammiribyan/zeroboot/blob/main/docs/API.md) [Architecture Docs](https://github.com/adammiribyan/zeroboot/blob/main/docs/ARCHITECTURE.md) [Deployment Guide](https://github.com/adammiribyan/zeroboot/blob/main/docs/DEPLOYMENT.md) [Homepage](https://zeroboot.dev) [GitHub](https://github.com/adammiribyan/zeroboot)

zeroboot-vm-sandbox