Recommended specs for a new server

I'm thinking of running a small Xonotic server. My plan is to use only vanilla maps, and nothing else. I will, however, have New Toys enabled on this server. I want to support up to twelve players at one time, on any vanilla gamemode.
What would the recommended minimum specs for this server be?

I'm not sure of the actual minimum, but I've had no problem hosting that many people on a $10/mo Digital Ocean droplet. Specs on that:

2 GB RAM, 1 vCPU, 50 GB SSD storage, 2 TB transfer, $10/mo $0.015/hr

What's more is that I've saved off a snapshot of that droplet for events (we do a lot of Xonotic stuff for company events where I work), which means I can spin up and tear down my server with a few button presses.

Thanks much, I set up my server using Digital Ocean's free trial with those settings.