Shaf makes it easy to expose your application through a REST API. Your business logic, however, is nothing that the Shaf framework should be mixed up with. Please put all your background jobs, services objects, commands etc in a src folder in the root of the project. This will make it easier to upgrade Shaf to newer versions in the future. Or if you find a better Ruby REST API framework, then it will be easier to just pull the src folder (plus relevant specs) and plug it into that framework instead. Ok, it might be a bit more work than that. But if your business logic is all mixed up with the framework, then that will most likely come back and bite you.