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Sandboxer vs Namespace Devboxes

Namespace Devboxes are VMs with persistent storage that stop when idle and restart on connect, available on Linux and Apple Silicon macOS. Max duration is 3 hours on Developer and 24 on Business. Pick Namespace for macOS or Docker-heavy CI-adjacent workflows; pick Sandboxer for long-running Linux VMs with nested KVM.

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

At a glance

Sandboxer and Namespace Devboxes compared
CapabilitySandboxerNamespace Devboxes
IsolationmicroVM
Cloud Hypervisor, its own kernel
full VM
Namespace says every agent gets a full VM.
Full Linux with root
Ubuntu 24.04, sudo, systemd
Docker inside
Preinstalled
Linux Devboxes run from a container image you choose and include Docker.
Nested virtualization (/dev/kvm)
Pause and resume with memory
Running processes come back
Fork a sandbox
Copy-on-write disk copy that boots fresh
HTTPS URL per port
Private with a token, or public
partial
Exposed ports get devbox.so URLs, but both access modes require sign-in; no public mode.
Longest sessionNo limit on paid plans
Auto-stop is up to 30 days or off
3 h (Developer, Devbox Plus), 5 h (Team), 24 h (Business)
Can be raised to 24 h via support.
BillingPer second, flat rate per size
Stopped sandboxes are free
per Devbox minute ($0.004; size multiplier S=1 to XL=8) plus storage $0.20/GB-month
GPUs
Self-host or open source
RegionsUS East (Virginia) and EU Central (Finland)

= not documented publicly.

Where Namespace Devboxes is strong

  • macOS (Apple Silicon) and Linux devboxes.
  • Idle auto-stop and restart on connect with persistent storage.
  • SDK, CLI and dashboard for creating devboxes.
  • Machine size, OS and base image are configurable, with SSH or GUI access for debugging.

Where Sandboxer differs

  • Namespace caps sessions at 3 to 24 hours; Sandboxer paid plans can run with no limit.
  • Namespace stop keeps storage, Sandboxer stop keeps memory and processes.
  • Namespace URLs require Namespace login; Sandboxer URLs can be public.
  • Namespace docs do not state nested KVM for devboxes or GPUs.

Pick Namespace Devboxes if

  • You need macOS devboxes on Apple Silicon.
  • You already use Namespace for CI and builds.
  • You need team workspace sharing of URLs.

Pick Sandboxer if

  • You need a full Ubuntu 24.04 VM with root, systemd, Docker and nested KVM, with agents like Claude Code and Codex preinstalled.
  • You want stop to save memory and disk and resume to bring processes back, with stopped sandboxes costing nothing.
  • You want a REST API, CLI, TypeScript and Python SDKs, and an MCP server on per-second billing.

Sources

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

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