The core PlayFab servers run in US-West Oregon is AWS. However, since the core service is entirely Web API based, and should only called a few times a minute per client in general, the latency difference should be negligible.
However, you can run custom game servers - which is what you would use for high-frequency server authoritative logic with clients - in any AWS region via the region setting on your build configuration.
Does this also mean , that photon and photon chat add-on region is only US-West. We are currently developing in South East Asia, when mobile data is used there's significant difference in delay with our call to playfab and our call to our internal server hosted in Singapore.
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