The US is so big, that 50 ms is physically not possible for everyone.
This is something that not everybody is aware of. When I as a German build something for germans, everyone who needs to wait longer than 100 ms for a request, is rightfully mad. But when I want to serve the same stuff to americans at the same speed, I have to build something completely different and much more complex.
Yeah, but you would need to run an API server in each of those to reach that latency, and even then you're well into eventually-consistent distributed system headache if you accept the POST without synchronising with all the others first.
You terminate SSL (err, TLS) at the pop so the clients TCP connection gets setup faster, and then you use a hot TCP connection from the pop to a centralized API server. That gets you not having to deal with the headache of running a distributed system but a better experience for the client.
If you want 50ms then you're gonna have to do the distributed systems headache that rcxdude was trying to avoid. For everything smaller than Google, that's too expensive, but it can be done.
