The point about VMs being the wrong shape because they’re tied to CPU/memory resonates hard. The abstraction forces you to pay for time, not work.

I ended up buying a cheap auctioned Hetzner server and using my self-hostable Firecracker orchestrator on top of it (https://github.com/sahil-shubham/bhatti, https://bhatti.sh) specifically because I wanted the thing he’s describing — buy some hardware, carve it into as many VMs as I want, and not think about provisioning or their lifecycle. Idle VMs snapshot to disk and free all RAM automatically. The hardware is mine, the VMs are disposable, and idle costs nothing.

The thing that, although obvious, surprised me most is that once you have memory-state snapshots, everything becomes resumable. I make a browser sandbox, get Chromium to a logged-in state, snapshot it, and resume copies of that session on demand. My agents work inside sandboxes, I run docker compose in them for preview environments, and when nothing’s active the server is basically idle. One $100/month box does all of it.

Vms hosted in Hetzner auction instances is exactly how shellbox works. I published more details in here: https://shellbox.dev/blog/race-to-the-bottom.html

This looks interesting at first blush.

My only feedback so far is that a lot of the documentation, though thorough and useful, looks clearly AI-written. That's not bad in and of itself, but it could be more concise. I especially love the "design decisions" section as I learned something new already.

Have you posted it on "Show HN" already? If not, you should.

> My agents work inside sandboxes

Out of interest, what sandboxing solution do you use?

OT - but Bhatti looks really cool! Well done!

Bhatti is a great name!