Sandkiln

Sandkiln is a compute primitive for safely running untrusted or AI-generated code in hardware-isolated microVMs.

Sandkiln provides hardware-isolated Firecracker microVMS to safely run untrusted or AI-generated code, agent output, user uploads, and third-party scripts. Every execution gets its own kernel, filesystem, and network using a Rust VMM, a static guest agent on vsock, and an HTTP daemon. It features a thin, fully-typed client with SDKs for JavaScript, TypeScript, and Python, alongside a CLI. It is self-hosted, MIT licensed, and benchmarked in the open. The platform targets developers who need secure code execution boundaries beyond shared kernel containers.

Sandkiln at a glance

Best for: Software engineer
Runs on: Web, CLI, self-hosted, open source
Pricing: Free
Released: October 2026
Category: AI coding tool
Website: sandkiln.vercel.app

Key features

Hardware-isolated Firecracker microVMs
JavaScript and TypeScript SDK
Python SDK
CLI tool
Self-hosted deployment
MIT licensed architecture
Open benchmarking

Use it for

Running untrusted code safely
Executing agent output and user uploads
Running third-party scripts securely

Alternatives to Sandkiln

microsandbox — Provides hardware-level isolation without needing daemons or complex setup.
Sandcastle — Orchestrates AI coding agents in isolated Docker, Podman, or Vercel sandboxes.
forkd — Spawns 100 isolated microVMs in approximately 100 milliseconds.
CubeSandbox — Provides sub-60ms cold starts and hardware-level microVM kernel isolation.
Agent Sandbox — Provides a secure and isolated execution layer for autonomous AI agents.
OpenSandbox — Provides isolated environments with multi-language SDKs and lifecycle management.
Popcorn — Runs untrusted code and Claude Code in microVMs isolated from your files and network
Daytona — It provisions sandboxes in under 90 milliseconds with full security isolation.
Lloyal — Builds apps with embedded models that run offline without user API keys.
SIwithin — Enforces strict budget caps and folder fences for AI agent CLIs.
Dormice — Permanent sandboxes that cost nothing while idle on private infrastructure.
AI Sandboxes by Buddy — Stateful virtual machines with persistent disks and public HTTPS endpoints.

All Sandkiln alternatives