How exe.dev works
You're an engineer. We're engineers. Let's talk about what's going on under the hood.
An "exe.dev" VM runs on a bare metal machine that exe.dev rents. We happen to use Kata Containers and Cloud Hypervisor, but that's a bit of an implementation detail (and may change!).
With most providers, your VM starts with a "base image" and is given a block device. Exe.dev instead starts with a container image (by default, "exeuntu"), and hooks up an overlay filesystem to the VM. This makes creating a new VM take about two seconds. In exchange, we lose some flexibility: you don't get to choose which filesystem you're using, nor which kernel you're using.
On the networking side, we don't give your VM its own public IP.
Instead, we terminate HTTPS/TLS requests, and proxy them securely
to your VM's web servers. For SSH, we handle ssh vmname.exe.xyz.