Systems and methods for efficiently and securely requesting and receiving, from a remote service, data for multiple accounts associated with the same device or application. In one example, a client device is configured to request application data for all accounts associated with the device or application installation using a single remote procedure call, rather than requiring separate calls for each account, and to do so by providing a single identifier rather than including identifiers specific to each associated account. The remote service is further configured to return the requested information in a manner that obfuscates the account identifiers and thus limits their potential use if the communication is intercepted, such that the application data can be efficiently transmitted together even where security or other concerns would otherwise dictate that separate transmissions should be made for each account.