As applications grow, dependency management becomes painful, tests get slower, and development becomes less joyful. Breaking up the application into services can be a great solution to these problems, but not every team is ready to leap fully into a SOA. Carson is Zendesk's compromise to this problem. It's a Rails 3 engine host: an application that contains only a Gemfile full of engines and some configuration. In this talk we'll explore the benefits and drawbacks of delivering features as engines and how this approach can act as a stepping stone from big-ball-of-mud architectures to service-oriented ones.