Methods, systems, and apparatus, including an apparatus for managing user data according to user consent settings are described. In some aspects, a method includes determining that a request for transmission by a client device to a recipient will include user data of a user of the client device. In response determining that the request will include the user data, the method includes requesting, from a consent management module of the client device, current user consent settings specified by the user which define at least one of (i) user data that can be transmitted from the client device, (ii) how user data transmitted from the client device can be used or (iii) which recipients can receive and retain user data from the client device. The method further includes receiving, from the consent management module, the current user consent settings and generating request data according the current user consent settings.