Sandboxer vs Self-hosted Firecracker

Firecracker is an open source (Apache 2.0) virtual machine monitor that creates lightweight microVMs using KVM. It is a component, not a service: you build the orchestration, networking, images and storage yourself. Pick it for full control and self-hosting; pick Sandboxer when you want it managed.

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

At a glance

Sandboxer and Self-hosted Firecracker compared
Capability	Sandboxer	Self-hosted Firecracker
Isolation	microVM Cloud Hypervisor, its own kernel	Firecracker microVM (KVM) Minimal device model with five emulated devices; jailer adds a second barrier.
Full Linux with root	Ubuntu 24.04, sudo, systemd	partial Linux guests you build yourself (kernel 4.14+ and a rootfs); root depends on your image.
Docker inside	Preinstalled	partial Possible inside a guest you build; not provided.
Nested virtualization (/dev/kvm)
Pause and resume with memory	Running processes come back	Snapshots capture guest memory and device state and resume in a new process; networking and uniqueness caveats apply.
Fork a sandbox	Copy-on-write disk copy that boots fresh	partial Resuming one snapshot multiple times is considered insecure unless you handle uniqueness; cloning needs extra network setup.
HTTPS URL per port	Private with a token, or public	You build the networking and proxying (TAP devices, iptables).
Longest session	No limit on paid plans Auto-stop is up to 30 days or off	no limit You own the host; no imposed limit.
Billing	Per second, flat rate per size Stopped sandboxes are free	none; you pay for your own hosts
GPUs		Not listed among its five emulated devices.
Self-host or open source		Apache 2.0.
Regions	US East (Virginia) and EU Central (Finland)	Wherever you run it

= not documented publicly.

Where Self-hosted Firecracker is strong

Open source under Apache 2.0, with a small attack surface and fast boot (under 125 ms).
Snapshot and resume of memory and device state.
Runs on your own x86_64 or aarch64 hardware.

Where Sandboxer differs

It is a building block: you build the control plane, images, networking, storage and agent tooling.
Snapshots must resume on identical hardware and software, with uniqueness caveats when cloned.
No GPUs, only five emulated devices.

Pick Self-hosted Firecracker if

You need full control, self-hosting or your own data centre.
You are building your own sandbox platform and have the engineering time.

Pick Sandboxer if

You want a full Ubuntu 24.04 VM with root, Docker and nested KVM that stops and resumes with running processes intact.
You want coding agents (Claude Code, Codex and others) preinstalled and driven through a prompt API, MCP, REST, CLI and SDKs.
You want per-second billing and stopped sandboxes that cost nothing.

Sources

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

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