Methods, systems, and apparatus include computer programs encoded on a computer-readable storage medium for delivering content. A method includes: identifying an application that is installed on a user device; accepting a bid from a sponsor associated with the application for presenting customized content on the user device after installation of the application on the user device; identifying an opportunity to present content on the user device including receiving a request for content that identifies the user device; conducting an auction including evaluating the accepted bid along with other bids; determining that the accepted bid is the winning bid in the auction and providing, in response to the determining, a shell for the customized content; enabling the shell to be populated with data stored on the user device to produce the customized content; and providing the customized content for presentation on the user device in response to the identified opportunity.