Examples of an application experiment system are provided that can manage and run experiments for software applications. In one embodiment, the application experiment system receives definitions for experiments and treatments for an application, runs experiments in response to requests from users of the system, automatically allocates treatments to users of the application, logs experiment data and treatment allocation data, and/or reports experiment results data. The application experiment system enables application developers to test changes or features in a precise, controlled environment on a limited user base before deciding whether to deploy changes or features to all users of an application.