Processing of requests to control information stored at multiple servers

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for transmitting/processing requests to control information stored at multiple content platforms/servers. In one aspect, a client device can send a request to verify the device's trustworthiness to a device trustworthiness server. The client device can receive, from the device trustworthiness server, data indicating that the client device is trustworthy, in response to which, the client device can send, to a relay server, a request to control user data stored at a plurality of servers. The client device can receive, via the relay server, a response from each of the plurality of servers. Based on the responses, the client device can determine that at least a subset of the plurality of servers that included the user data has performed the action specified in the request to control the user data.