In the specific case of Notado, the Tailscale tunnel between Fly and Digital Ocean for database access naturally introduces some minimal additional latency.

Besides this, I'm not sure I'm in the best position to compare the latency and performance of a service running 100% on a Digital Ocean VPS vs. a Fly.io micro VM. Hopefully someone else can chime in with their experiences on this thread.

I think that fly.io is still using firecracker for their microvm offering, although qemu has a similar machine type implemented.

Having worked on firecracker and with firecracker, it does a good job in the networking area.

Note that there's no multiqueue implementation available, so depending on how many connections and data you're passing through, it may start struggling if the workload is high.

I don't know the specifics of how DO sets up their VMs, but I assume that they're not doing any fancy networking optimizations, so you may end up with similar issues on both setups.