Bartalog
commented
4 years ago Also, it turns out that App Engine's global routes have huge latency problems when the client communicates to an instance in a different region.
This can be solved by calling only App Engine's newer regional routes (e.g. ending with .uc.r.appspot.com).
We can expect that communication between mobile, server, and target, would have less latency if it doesn't need to cross Atlantic or Pacific oceans.
Make sure the backend, the file server, and the server push system are properly distributed. Measure latency from various locations in the world.