App Engine locations

App Engine applications are region-specific. When creating an App Engine application, users specify the region on which to run their services. All services and instances will be colocated within this region and spread across the zones within that region. Almost all regions support App Engine, with the following exceptions:

• Oregon (us-west1)
• Singapore (asia-southeast1)
• Taiwan (asia-east1)

Note that once the App Engine region has been selected for a project, it cannot be changed. When choosing a region, there are a couple of considerations to make. First, consider the geographical distribution of your current (and expected) user base as latency will largely be determined by the physical distance between users and your App Engine region. Google largely mitigates this latency through load balancers that allow requests to be routed to nearby points of presence and transmitted across Google's internal network.

Another consideration when choosing an App Engine region is where other components of your system will be located. For example, if your App Engine applications heavily interact with Compute Engine VMs in Iowa (us-central1), it may make sense to use that same region for App Engine. This will both reduce latency and costs incurred from cross-region traffic. For solutions that largely depend on App Engine, consider locating other GCP resources in the region that best suits your App Engine services. For example, App Engine cannot be hosted in the us-west1 region, so projects that depend heavily on App Engine should likely avoid deploying other core services to this region, or structure them to be multi-regional.