Sandboxes I've tried

I've been testing ways to run sandboxes that hold my development environment and Claude Code, and exposing them through a web interface. I'm trying to turn this into a basic product that lets non-technical people edit their own websites.

Here's what I've tried:

• Firecracker: not great for long-running tasks. Snapshotting is time consuming and it's not great with a large number of files.
• Docker: this seems great but it's a lot to manage. I had a DigitalOcean droplet spinning up the containers. Docker caches them for you automatically, which is great, but it's a limited environment.
• Fly.io: I hit bugs in the dashboard and it was a pain.
• Fly.io Sprites: I hit bugs with "warming" vs "running" states, and it seemed very slow.
• EC2: AWS still has the fastest instance spin-up and the lowest cost for running instances, but the boot time isn't going to work for my use case.

So I tried Firecracker again, this time on a bare metal Hetzner server. The VMs spin up in 2 seconds. The slowest part is npm install, which dependency caching could improve.

It's working pretty well, but I'm not sure I want to manage Firecracker and a bare metal server. So I'm looking at exe.dev and shellbox.dev, which do exactly this as a service.