CreateOS Sandbox vs Blacksmith
Blacksmith is the easy win for teams on GitHub Actions who want faster, cheaper CI by changing one runs-on line. CreateOS Sandbox is for agents that need a Firecracker micro-VM on demand through an API, outside any workflow. Both use Firecracker; Blacksmith's microVMs are reachable only as GitHub Actions jobs, and it lists a separate Sandboxes product as coming soon.
Pricing at a Glance
CreateOS rates verified 17 October 2026. Blacksmith pricing as published on 17 October 2026. Rates billed per GB rather than per GiB, or as bundled sizes, are quoted as published rather than converted.
CreateOS Sandbox
- Compute
- $0.0362 /vCPU-hr
- Memory
- $0.0116 /GiB-hr
Blacksmith
Blacksmith charges per minute: Ubuntu x64 $0.004, Ubuntu ARM $0.0025, Windows x64 $0.008 and macOS M4 $0.08, with 3,000 free minutes per month and add-ons such as $0.50/GB-month for sticky disks, as of 17 October 2026.
Where CreateOS Sandbox Fits Better
What CreateOS Sandbox brings to this matchup, with a plain note on where Blacksmith has the edge.
Reachable through REST, SDKs, a CLI and MCP today; Blacksmith runners are reachable only as GitHub Actions jobs.
Keep and branch a micro-VM: pause, resume and fork. Blacksmith runners are ephemeral per job.
Inbound HTTPS when asked for; Blacksmith runners take no inbound traffic.
Where Blacksmith is strong
Fast, cheap GitHub Actions with no workflow rewrite: Firecracker microVM isolation per job, high single-thread CPUs and caching co-located with the runners.
Which to Pick
Pick CreateOS Sandbox if
- Your agent needs a micro-VM outside a CI workflow
- Sessions are interactive or need a public URL
- You want to pause and resume the same machine
Pick Blacksmith if
- Your CI is on GitHub Actions and you want it faster and cheaper
- You need Windows or macOS M4 runners
- You want sticky disks and Docker layer caching for builds
Head-to-Head Comparison
Every dimension side by side, checked on 17 October 2026 against each vendor's own docs and pricing pages. "Not published" means we could not find it on the vendor's pages, not that the feature is missing.
| Dimension | CreateOS Sandbox | Blacksmith |
|---|---|---|
| Built for | API-created sandboxes for agent-written and untrusted code | Drop-in GitHub Actions runners |
| Isolation | Firecracker micro-VM with its own guest kernel | Firecracker microVM per job (Linux and Windows), ephemeral |
| Trigger model | API, SDK, CLI or MCP call, on demand | GitHub Actions runs-on labels |
| Session length | No cap; optional idle auto-pause from 60 s to 24 h, off by default | Not published; follows GitHub Actions job limits |
| Pause and resume | Yes. Saves disk, memory and CPU state; vCPU stops billing while paused, memory and storage still bill | Not published; runners are ephemeral, sticky disks persist data across jobs |
| Outbound network | Open with no rules; deny-by-default once any rule exists (host, IP, CIDR, wildcard), enforced on the host outside the VM | Not published; static IPs as a $100/IP/month add-on |
| Billing | Per second: $0.03616363/vCPU-hr, $0.01159025/GiB-hr, storage $0.0001584/GB-hr; no egress fees (50 GiB bandwidth budget per sandbox by default) | Per minute by runner type |
Common Questions
Do Blacksmith and CreateOS use the same isolation?
Both use Firecracker microVMs. Blacksmith runs one ephemeral microVM per GitHub Actions job on Linux and Windows. CreateOS runs one per sandbox, with its own guest kernel, and the sandbox persists until you destroy it.
Does Blacksmith sell sandboxes?
Not yet. Blacksmith lists a separate Sandboxes product as coming soon; today its runners are reachable only as GitHub Actions jobs. CreateOS Sandbox is available through REST, a CLI, an MCP server and six SDKs.
Which regions does Blacksmith run in?
Blacksmith lists us-east (Ashburn), us-west (Phoenix), eu-west (Amsterdam) and eu-central (Frankfurt). CreateOS Sandbox has two managed regions, eu and us, chosen when a sandbox is created.
Sources
Checked 17 October 2026.
See CreateOS Sandbox for yourself
Book a demo, or explore the Sandbox and its pricing.