Sandboxer vs shellbox

shellbox gives on-demand Linux microVMs over plain SSH; your key fingerprint is your account, and idle boxes pause with memory. Sandboxer offers a REST API, SDKs and bundled coding agents. Pick shellbox for a minimal SSH workflow; pick Sandboxer for APIs, agents and larger sizes.

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

At a glance

Sandboxer and shellbox compared
Capability	Sandboxer	shellbox
Isolation	microVM Cloud Hypervisor, its own kernel	microVM (Firecracker default, Cloud Hypervisor with --ch) Firecracker by default; Cloud Hypervisor with --ch.
Full Linux with root	Ubuntu 24.04, sudo, systemd	SSH logs in as root.
Docker inside	Preinstalled	Stock Ubuntu 24.04 boxes have Docker preinstalled; OCI-image boxes do not.
Nested virtualization (/dev/kvm)		partial Only with the Cloud Hypervisor backend (--ch); not on the default Firecracker backend.
Pause and resume with memory	Running processes come back	Pauses 120 s after the last SSH disconnect; processes and files restored on reconnect in about 3 s.
Fork a sandbox	Copy-on-write disk copy that boots fresh	partial duplicate makes a point-in-time copy of a stopped box (copy-on-write disk); memory state carrying over is not stated and a halted box's memory snapshot is discarded.
HTTPS URL per port	Private with a token, or public	partial One HTTPS URL per box proxies to port 80; other ports via public IPv6 or SSH forwarding.
Longest session	No limit on paid plans Auto-stop is up to 30 days or off	Limited to 16 running slots and 64 total slots per account; no time limit stated.
Billing	Per second, flat rate per size Stopped sandboxes are free	per minute while running, per slot $0.02/h per x1 slot running, $0.50/month per x1 slot parked.
GPUs		not stated on the official pages read
Self-host or open source		not stated on the official pages read
Regions	US East (Virginia) and EU Central (Finland)	Hetzner Finland (one region); US planned

= not documented publicly.

Price for one 4 vCPU, 8 GB machine

Sandboxer

$0.036/hour

Flat per-second rate for the default size

shellbox

$0.040/hour

x2 box (2 slots x 2 vCPU / 4 GB = 4 vCPU / 8 GB) at $0.02/h per x1 slot; the FAQ says billing scales proportionally with size

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

Where shellbox is strong

No signup: the SSH key fingerprint is the account.
Root, Docker and nested KVM (with --ch) are documented.
Memory-snapshot pause and resume in about 3 seconds.
Pricing is simple per slot and refundable within three months for unused funds.

Where Sandboxer differs

shellbox is SSH-first with a small API surface; Sandboxer adds a REST API, OpenAPI, SDKs and an MCP server.
shellbox exposes one HTTPS port per box; Sandboxer gives any port as an HTTPS URL.
shellbox caps accounts at 16 running slots; Sandboxer plans set concurrency up to 2000.

Pick shellbox if

You want no account setup and a plain SSH workflow.
You want the option of Cloud Hypervisor with /dev/kvm at a low slot price.

Pick Sandboxer if

You want a full Ubuntu 24.04 VM with root, systemd, Docker and nested KVM, with Claude Code, Codex and other coding agents preinstalled.
You want stop to save memory and disk so that resume brings running processes back, with stopped sandboxes costing nothing.
You want one flat monthly plan whose dollars come back as machine time, with sandboxes that can run with no time limit on a paid plan.

Sources

shellbox home

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

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