In one implementation, a computer-implemented method includes receiving, at a computer system and from a first computing device, a request to access a simulation of an application running a second computing device; identifying, by the computer system, one or more types of input that are available on the second computing device and that are not available on the first computing device; generating one or more controls for each of at least a portion of the identified types of input; instantiating, by the computer system, a virtual machine that simulates the second computing device; and providing information to the first computing device that causes i) an interface for the application as executed by the virtual machine to be presented by the first computing device and ii) the generated controls to be presented by the first computing device in association with the interface.