The data centers are in North America. For the most part, users in the United States will not notice latencies. For users outside the United States, the request goes like this:
- Request goes to a geographically close Google front end data center
- From the Google data center, requests are routed to App Engine data center(s). This'll be faster than if a user were to access the App Engine data centers directly, but there will be latency
Requests for static content or images served via the high performance image serving API are usually served off a close by data center.
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Ikai Lan
Developer Programs Engineer, Google App Engine