# Cloudflare Sandbox vs Prime Sandboxes: pricing and fit

Runtime Cloud (withruntime.com) bills $0.64 on the benchmark. Cloudflare suits Workers apps, and Prime suits large RL runs.

## Which is better, Cloudflare Sandbox or Prime Sandboxes?

It depends on whether you serve users or train models. For agents that wait on a model, Runtime has the lowest cost, $0.64 on the benchmark against $1.35 on Cloudflare and $1.52 on Prime, and it keeps a sandbox's memory across pauses. Pick Cloudflare Sandbox for Workers apps that want sandboxes at the edge; pick Prime Sandboxes for large, parallel RL rollouts, with 1,024 sandboxes to start.

## At a glance

|           | Cloudflare Sandbox                                                           | Prime Sandboxes                                | Runtime                                                        |
| --------- | ---------------------------------------------------------------------------- | ---------------------------------------------- | -------------------------------------------------------------- |
| Isolation | A container in its own VM                                                    | Hardware-virtualized microVM, own guest kernel | Firecracker microVM, own kernel                                |
| CPU       | $0.072 per active vCPU-hour                                 | $0.02 per vCPU-hour while running | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory    | $0.009 per provisioned GiB-hour, 3 GiB per vCPU at least | $0.0125 per GiB-hour             | $0.0075 per reserved GiB-hour                          |
| Largest   | 4 vCPUs, 12 GiB, 20 GB                                                       | 16 vCPUs, 64 GiB, 128 GiB of disk              | 16 vCPUs and 64 GiB, paid                    |
| Idle      | Filesystem-only snapshots; processes restart                                 | Idle timeout off by default                    | Pause keeps memory while you have credit                       |
| Fleet     | 1,500 vCPUs per account                                                      | 1,024 sandboxes, 4,096 vCPUs to start          | 100 sandboxes, 200 vCPUs                         |

## Edge or scale

Cloudflare places a sandbox near the user who asked for it and bills only the
CPU that works, but forces memory up with CPU. Its public-beta snapshots
preserve files after a stop, but not memory or processes.
Prime runs large microVMs in the thousands at a flat low rate. Both suit short
tasks; neither keeps a sandbox's memory between steps today.

## Cost for the same job

The benchmark, 60 seconds a run (6 GiB and a 12 GB disk on Cloudflare, 5 GiB
of disk on Prime):

```
Cloudflare  CPU    1,000 × 20 s × $0.000020                     = $0.40
            Memory 1,000 × 60 s × 6 × $0.0000025                = $0.90
            Disk   1,000 × 60 s × 12 × $0.00000007              = $0.05
            Total                                                  $1.35

Prime       CPU    1,000 × 60 s / 3,600 × 2 × $0.02              = $0.67
            Memory 1,000 × 60 s / 3,600 × 4 × $0.0125            = $0.83
            Disk   1,000 × 60 s / 3,600 × 5 × $0.0002            = $0.02
            Total                                                  $1.52

Runtime     CPU    1,000 × 20 s / 3,600 × $0.025                = $0.14
            Memory 1,000 × 60 s / 3,600 × 4 × $0.0075           = $0.50
            Total                                                  $0.64
```

With both CPUs busy for the whole minute, the job costs $3.35 on Cloudflare, $1.52 on Prime and $1.33 on Runtime.

## Which one to pick

- **Cloudflare Sandbox** for Workers apps that want sandboxes at the edge.
- **Prime Sandboxes** for large, parallel RL rollouts.
- **Runtime** for the lowest cost and memory kept across pauses.

See [Runtime vs Cloudflare Sandbox](/docs/cloudflare-sandbox-alternative) and
[Runtime vs Prime Sandboxes](/docs/prime-sandboxes-alternative).

## Runtime Cloud

Runtime costs 53% less than Cloudflare and 58% less than Prime on it.
1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox with 20 CPU-seconds of work
each: $1.35 on Cloudflare Sandbox (priced at its 6 GiB minimum), $1.52 on
Prime Sandboxes and $0.64 on Runtime.

Try Runtime free through `npx withruntime login`. If your code already runs on another provider, the [migration guide](/docs/migrate) shows the switch.

## Sources

- [Cloudflare sandbox lifetime](https://developers.cloudflare.com/sandbox/concepts/lifetime/), snapshot behavior checked 25 October 2026.
  Cloudflare rates checked 25 October 2026; Prime Sandboxes rates checked 25 October 2026.

- [Cloudflare Containers pricing](https://developers.cloudflare.com/containers/pricing/), [Containers limits and instance types](https://developers.cloudflare.com/containers/platform/limits/)
- [Prime Sandboxes overview](https://docs.primeintellect.ai/sandboxes/overview), [Prime Sandboxes launch](https://www.primeintellect.ai/blog/sandboxes)
- Runtime [pricing](/docs/pricing)

Facts on this page were checked on 26 October 2026.