Sandboxer vs Railway Sandboxes

Railway Sandboxes are isolated, ephemeral Linux VMs created from the Railway CLI, SDK or API, with disk checkpoints, forks, up to 10 HTTPS domains per sandbox and private-network access to Railway services. They are best when your agents need to reach Postgres or Redis in a Railway environment; Pick Sandboxer for long-lived full VMs where resume brings processes back.

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

At a glance

Sandboxer and Railway Sandboxes compared
Capability	Sandboxer	Railway Sandboxes
Isolation	microVM Cloud Hypervisor, its own kernel	Linux VM (hypervisor not named) Docs call it an isolated, ephemeral Linux VM.
Full Linux with root	Ubuntu 24.04, sudo, systemd
Docker inside	Preinstalled
Nested virtualization (/dev/kvm)
Pause and resume with memory	Running processes come back	Checkpoints save disk state only; processes and memory are not copied.
Fork a sandbox	Copy-on-write disk copy that boots fresh	partial Fork clones the filesystem of a running sandbox; running processes do not carry over (same as Sandboxer fork).
HTTPS URL per port	Private with a token, or public	Up to 10 Railway HTTPS domains per sandbox, one per port; needs PRIVATE networking.
Longest session	No limit on paid plans Auto-stop is up to 30 days or off	no maximum stated; idle timeout 5 min (Free) or 30 min default, up to 120 min or never on Hobby/Pro
Billing	Per second, flat rate per size Stopped sandboxes are free	per second, memory in use + CPU actively used + egress Idle sandboxes still bill for memory.
GPUs
Self-host or open source		Hosted; only the TypeScript SDK is open source.
Regions	US East (Virginia) and EU Central (Finland)	US West, US East, EU West, Southeast Asia

= not documented publicly.

Price for one 4 vCPU, 8 GB machine

Sandboxer

$0.036/hour

Flat per-second rate for the default size

Railway Sandboxes

$0.83/hour

VM rates: 4 vCPU × $0.001157/min × 60 + 8 GB × $0.001157/min × 60 (billed only for CPU actively used, so real cost is lower for idle machines)

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

Where Railway Sandboxes is strong

Four regions with sandboxes available on every plan, including Free.
Private networking to other Railway services such as Postgres and Redis.
Checkpoints and forks, plus coding agents (Claude Code, Codex, OpenCode, Pi) preinstalled.
CPU billed only while busy.

Where Sandboxer differs

Resume does not bring processes back; checkpoints and forks are disk-only.
Docs do not state root, Docker or nested KVM; Sandboxer provides all three.
Default idle timeout is 5 minutes on Free and 30 minutes on paid plans.
Memory-in-use stays billable while idle; Sandboxer stopped machines cost nothing.

Pick Railway Sandboxes if

Your app already runs on Railway and agents need private-network access to its services.
You want sandboxes on the free plan and multiple regions.
You want CPU charged only while actually busy.

Pick Sandboxer if

You want stop/resume that restores running processes.
You want root, systemd, Docker and nested KVM in a full Ubuntu VM.
You want SSH and an MCP server in every sandbox.

Sources

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

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