Methods, systems, and apparatus, including computer programs encoded on computer storage media, for testing performance of server systems. In some implementations, a method includes identifying, by one or more computers, a resource provided by a server system. The method includes generating, by the one or more computers, a performance test for the server system. The performance test includes a series of operations that includes (i) providing the resource and (ii) responding to one or more interactions with the resource. The method includes performing one or more performance testing cycles that each include: causing the server system to perform the series of operations of the performance test; and evaluating one or more performance measures that characterize the performance of the series of operations by the server system.