CreateOS Sandbox vs OpenReward
OpenReward is the pick for research and post-training teams running agentic RL or evals, since it serves 380+ ready environments over one API with autoscaled sandboxes and an nvidia-l4 option. CreateOS Sandbox is the pick for general agent or user code in product features, where you need egress allowlists, pause and fork, and one published rate card.
Pricing at a Glance
CreateOS rates verified 17 October 2026. OpenReward 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
OpenReward
OpenReward bills time spent in the sandbox at rates set per environment, for example $0.0000780 per second in total on the DAComp-DA environment page; no general rate card is published, as of 17 October 2026.
Where CreateOS Sandbox Fits Better
What CreateOS Sandbox brings to this matchup, with a plain note on where OpenReward has the edge.
Egress allowlists by host, IP, CIDR or wildcard; OpenReward offers open egress or block_network and publishes no allowlist.
One published rate card for every sandbox, against rates set per environment.
Pause with memory and fork from a paused sandbox; OpenReward publishes no cross-session persistence.
Firecracker micro-VM with its own guest kernel, where OpenReward uses isolated, ephemeral containers.
Where OpenReward is strong
It gives RL teams hundreds of ready environments and millions of tasks behind one API that plugs into training frameworks such as Tinker, Miles and Slime, so they skip building environments and sandbox autoscaling.
Which to Pick
Pick CreateOS Sandbox if
- You run agent or user code inside a product, not RL training.
- Sandbox code must reach only approved destinations.
- You want to save an agent mid-task and branch from that state.
Pick OpenReward if
- You train or evaluate agents with RL rollouts and want ready environments.
- You use Tinker, Miles or Slime and want an environment API that plugs in.
- Your rollouts need an nvidia-l4 GPU.
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 | OpenReward |
|---|---|---|
| Isolation | Firecracker micro-VM with its own guest kernel | Isolated, ephemeral containers; runtime not published |
| Pause and resume | Pause saves disk, memory and CPU state; vCPU stops billing, memory and storage still bill | Sandbox created at session start and stopped in teardown; no cross-session persistence published |
| Fork | Yes, fork a paused sandbox into many independent copies | Not published |
| Outbound network default | Open with no rules; deny-by-default once any host, IP, CIDR or wildcard rule exists, enforced on the host outside the VM | Open by default; block_network=True isolates; no allowlist published |
| Largest size | 8 vCPU / 16 GB on Enterprise; 8 vCPU / 8 GB on Pro | Listed CPU:memory sizes up to 4:16 (units not stated) |
| Concurrency | 1 / 5 / 20 / 30 by plan; paused sandboxes count toward the cap | Not published (vendor-stated: autoscales for rollout bursts) |
| Session length | No cap; idle auto-pause 60 s to 24 h, off by default | Not published |
| Billing | Per second: $0.03616363 per vCPU-hour, $0.01159025 per GiB-hour, storage $0.0001584 per GB-hour; no egress fees, 50 GiB bandwidth budget per sandbox | Per second per session, at rates set per environment |
| SDKs and interfaces | TypeScript, Go, Python, Rust, C#, Java SDKs (all but TypeScript pre-1.0), CLI, MCP, REST | Python SDK; Open Reward Standard (ORS) protocol |
| GPU | No GPU shapes | Yes, nvidia-l4 option listed |
Common Questions
What is OpenReward used for?
Training and evaluating agents with reinforcement-learning rollouts against 380+ hosted environments, where tool calls run in per-session sandboxes. CreateOS Sandbox is a general-purpose sandbox for agent or user code and has no environment catalogue.
Is outbound internet open in OpenReward sandboxes?
Yes. OpenReward states that all egress is allowed by default, and block_network=True isolates a sandbox; no allowlist is published. CreateOS Sandbox is also open with no rules, but switches to deny-by-default once you add any host, IP or CIDR rule.
Can OpenReward use other sandbox providers?
Yes. OpenReward supports third-party sandboxes from E2B, Daytona and Modal alongside its own containers. Environment servers can be self-hosted, but they must connect to an OpenReward environment space to use its sandbox compute.
Sources
Checked 17 October 2026.
See CreateOS Sandbox for yourself
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