Abstract: Techniques are disclosed relating to the communication between server systems located in different network regions. For example, in some embodiments, a first server system located in a first network region may receive a request to perform a first operation for a user, where the request includes an alias value for the user. The first server system may determine, based on the alias value, that the user is not associated with the first network region. In response, the first server system may access an alias map that specifies encoded versions of alias values that are in use across multiple different network regions and, using the alias map, determine that the user is associated with a second network region. The first server system may then route a communication corresponding to the request to a second server system that is located in the second network region.

Abstract: Techniques are disclosed relating to verifying that an alias value is unique across multiple different network regions. In various embodiments a server system located in a first network region may maintain an alias map that specifies encoded versions of alias values that are in use across multiple different network regions. For example, for a given alias value, the alias map may specify a corresponding encoded version of the alias value and an identifier for a given one of the network regions with which the given alias value is associated. In various embodiments, the server system may receive a user-provided alias value from a user during an account registration process and, using the alias map, determine whether the user-provided alias value is already in use in any of the network regions.