It has been pointed out to us that since we have our servers in the US, we are under US jurisdiction. We do not believe this to be the case.
https://blog.fastmail.com/2013/10/07/fastmails-servers-are-i...
As a non-lawyer I would expect the US to be able to serve their host with a warrant to get whatever data the judge said they could have.
on FastMail alone I did not like how slow it is. I was testing them and Protonmail at the same time and was very impress how simple it is to setup my multiple domains/users on Proton and how fast encryption/decryption works. And Protonmail "[...] is outside of US and EU jurisdiction, only a court order from the Cantonal Court of Geneva or the Swiss Federal Supreme Court can compel us to release the extremely limited user information we have.[...] [1]
https://protonmail.com/security-details
Full disclosure: I don't work for Proton; I'm just their happy mailer :)
EDIT: Slow I mean their GUI comparing to Proton. It might be more the number of extensions I have to block or limit different shenanigans such as AdBlock etc.. but needless to say, Proton does not have that problem.
> We do not participate in, or co-operate with, any kind of blanket surveillance or monitoring. (We also point out that Australia does not have any equivalent to the US National Security Letter, so we cannot be forced to do something without being allowed to disclose it.)
So while they cannot harvest data and then share it in bulk, they can access data in individual cases and share it with law enforcement.
At the very least, anything that the US would try would be noticed by someone who is not subject to US gag orders. Potentially they can get Australia to provide those orders, but now it is an international thing, which is more difficult than the US going alone.