Hi there
This is exactly what multiprocess Fly apps are for. You can scale the workers and api independent of each other, as they get each get their own VM. Both are behind the same public IP, however. And if you intend to use 6pn (Fly’s private network), this setup may not work as intended.
If you’re looking to use the latest and greatest, for cron jobs, have a look at: New feature: Scheduled machines
And for api, run them in Machines (Apps v2).
There’s multi-process Machines which in fact run all processes on all VMs, but it doesn’t seem like that’s what you want.