Sandboxer vs smol machines

smol machines provides hardware-isolated Linux microVMs through the open-source smolvm engine, which runs on macOS, Linux and Windows, and a managed smol cloud. It differs from Sandboxer by being portable, self-hostable and GPU-capable, while Sandboxer is a hosted full Ubuntu VM with Docker and nested KVM. Pick smol machines for local-to-cloud portability and self-hosting; pick Sandboxer for a managed full VM.

Checked against smol machines' public docs on October 24, 2026. Sources are linked in the table and listed below.

At a glance

Sandboxer and smol machines compared
Capability	Sandboxer	smol machines
Isolation	microVM Cloud Hypervisor, its own kernel	microVM (libkrun; KVM, Hypervisor.framework or WHP) Own guest kernel.
Full Linux with root	Ubuntu 24.04, sudo, systemd
Docker inside	Preinstalled	partial Docs include a guide for running a Docker daemon inside a machine.
Nested virtualization (/dev/kvm)
Pause and resume with memory	Running processes come back	partial Checkpoint and restore exist; memory-state pause not confirmed.
Fork a sandbox	Copy-on-write disk copy that boots fresh	'machine branch' makes a copy-on-write clone of a running, branchable machine; not on native Windows.
HTTPS URL per port	Private with a token, or public
Longest session	No limit on paid plans Auto-stop is up to 30 days or off
Billing	Per second, flat rate per size Stopped sandboxes are free	base fee per running machine-hour + consumed vCPU-hours and GB-hours $0.04/machine-hour base, $0.05/vCPU-hour consumed, $0.0162/GB-hour in use; 1-minute minimum, then to the second; stopped machines pay disk only.
GPUs		partial Vulkan via virtio-gpu; CUDA via API remoting from v1.5.0.
Self-host or open source		smolvm engine and CLI are open source and can be self-deployed.
Regions	US East (Virginia) and EU Central (Finland)	Custom deployments on designated-location hosts on request.

= not documented publicly.

Price for one 4 vCPU, 8 GB machine

Sandboxer

$0.036/hour

Flat per-second rate for the default size

smol machines

$0.37/hour

$0.04 base + 4 vCPU × $0.05/h + 8 GB × $0.0162/h (assumes full consumption)

List prices from each provider's pricing page, before free credits, plans and storage. This compares price only.

Where smol machines is strong

Open source engine that also runs on a laptop.
Copy-on-write branching of running machines.
Self-hosting supported.
GPU workloads via Vulkan and CUDA remoting.

Where Sandboxer differs

smol machines is portable and self-hostable; Sandboxer is hosted only.
Cloud billing is per consumed resource plus a base fee, while Sandboxer prices fixed sizes.
Nested virtualization, root and public per-port URLs are not stated in the docs fetched.

Pick smol machines if

You want to run the same microVM locally, self-hosted and in a cloud.
You need GPU workloads in an isolated guest.
You want an open-source engine.

Pick Sandboxer if

Your workload needs a full Ubuntu VM with systemd, Docker preinstalled and nested KVM.
You want coding agents (Claude Code, Codex, OpenCode, Pi, Kimi Code, Mistral Vibe) preinstalled and driven through a prompt API.
You want stop/resume that keeps memory and running processes, with sessions that can run with no time limit on a paid plan.

Sources

Products change. If something here is out of date, email hello@sandboxer.com and we'll fix it. smol machines is a trademark of its owner. Sandboxer is an independent product and is not affiliated with smol machines.

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