Comment by janekm

Regarding hosting, it's a big pain point for companies building these systems out of China as the "great firewall" makes it really hard to have reliable connectivity between the Chinese Internet (and datacenters) and outside. The ap-east-1 zone of AWS, based in Hong Kong, is very popular in that context as it tends to be accessible from both sides (so cost is fairly typical of AWS costs in that case). Alternatively Alibaba also have cloud datacenters in Hong Kong with similar properties.