We rolled out our own that does pretty much the same thing but perhaps more because our solution can also mount persistent storage that can be carried between multiple runners. It does take 1-5 seconds to boot the environment (firecracker vms). If this sandbox is faster I will instruct the team to consider for fast starup.

This is also very similar to Vercel's sandbox thing. The same technology?

What I don't like about this approach is the github repo bootstrap setup. Is it more convenient compared to docker images pushed to some registry? Perhaps. But docker benefits from having all the artefacts prebuilt in advance, which in our case is quite a bit.

It's the same SDK stuff from earlier this year right? https://developers.cloudflare.com/changelog/2025-06-24-annou...

As far as I can tell it's all or nothing right now:

  this.ctx.container.start({
    enableInternet: false,
  });

As such, I'd like to be able to allow-list just specific network points. Maybe I'm OK with the container talking to an API I provide but not to the world at wide. Or perhaps I'm OK with it fetching data from npm and PyPI but I don't want it to be able to access anything else (a common pattern these days, e.g. Claude's Code Interpreter does this.)

Memory: $0.0000025 per additional GiB-second vCPU: $0.000020 per additional vCPU-second Disk: $0.00000007 per additional GB-second

The smaller instance types have super low processing power by getting a fraction of a vCPU. But if you calculate the monthly cost then it comes to:

Memory: $6.48 per GB vCPU: $51.84 per vCPU (!!!) Disk: $0.18 per GB

These prices are more expensive than the already expensive prices of the big cloud providers. For example a t2d-standard-2 on GCP with 2 vCPUs and 8GB with 16GB storage would cost $63.28 per month while the standard-3 instance on CF would cost a whopping $51.84 + $103.68 + $2.90 = $158.42, about 2.5x the price.

Cloudflare Containers also don't have peristent storage and are by design intended to shut down if not used but I could then also go for a spot vm on GCP which would bring the price down to $9.27 which is less than 6% of the CF container cost and I get persistent storage plus a ton of other features on top.

What am I missing?

The docs claim they persist the filesystem even when they move the container to an idle state but its unclear exactly what that means - https://github.com/cloudflare/sandbox-sdk/issues/102

Instead of having to code this up using typescript, is there an MCP server or API endpoint I can use?

Basically, I want to connect an MCP server to an agent, tell it it can run typescript code in order to solve a problem or verify something.