Where it runs
Your service runs in the region you choose, on machines from more than one provider. You don't depend on a single one doing well.
Choose close to your database
There are two: the United States (us) and Europe (eu). Your service stays in its region, also when it moves. Only if there were no room there would it run in another for a while, and it comes back as soon as there is room. Put it where your database is: every query travels less. spredr suggests the region by reading your database’s address in your variables.
More than one provider behind it
Your service lives on machines paid by the month, and if one falls another from a different provider takes over. Today the base is Contabo and the backup is Google Cloud; OVH, AWS and Azure are on the way.
What matters for you: if a provider has a bad day, your service keeps going on another.