Sandboxer vs Celesto Cloud

Celesto Cloud hosts microVM sandboxes built on the Apache-2.0 SmolVM core, so you can run the same runtime yourself. Sizes use shared vCPUs from $0.015/h. Sandboxer is closed-source with root, Docker and nested KVM. Pick Celesto for open source and self-hosting; pick Sandboxer for a full VM with bundled agents.

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

At a glance

Sandboxer and Celesto Cloud compared
Capability	Sandboxer	Celesto Cloud
Isolation	microVM Cloud Hypervisor, its own kernel	microVM (SmolVM) Hardware-level separation per Celesto's docs.
Full Linux with root	Ubuntu 24.04, sudo, systemd	not stated on the official pages read
Docker inside	Preinstalled	not stated on the official pages read
Nested virtualization (/dev/kvm)		not stated on the official pages read
Pause and resume with memory	Running processes come back	Idle sandboxes suspend and resume in milliseconds with running processes kept.
Fork a sandbox	Copy-on-write disk copy that boots fresh	Branch a running sandbox into parallel copies.
HTTPS URL per port	Private with a token, or public	Apps, APIs and previews can be exposed from inside the sandbox; URL format not read.
Longest session	No limit on paid plans Auto-stop is up to 30 days or off	not stated on the official pages read
Billing	Per second, flat rate per size Stopped sandboxes are free	hourly rate by size, running time only Granularity not stated; stopped root disks kept free for 30 days.
GPUs		not stated on the official pages read
Self-host or open source		Apache-2.0 core runs on your own infrastructure with no account.
Regions	US East (Virginia) and EU Central (Finland)	not stated on the official pages read

= not documented publicly.

Where Celesto Cloud is strong

Open-source Apache-2.0 core that you can self-host.
Low entry price: $0.015/h for 1 shared vCPU / 2 GB.
No subscription or monthly minimum.
Fork and suspend/resume are advertised.

Where Sandboxer differs

Celesto vCPUs are listed as shared and top out at 8; Sandboxer sizes range from 2 to 16 vCPU VMs.
Celesto can be self-hosted; Sandboxer cannot.
Root, Docker, nested virtualization, session limits and regions are not stated on the pages read.

Pick Celesto Cloud if

You want an open-source runtime you can self-host or audit.
You want the cheapest small sandboxes for light tasks.

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

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

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