```rails new my_api --api````
*Configure your application to start with a more limited set of middleware than normal. Specifically, it will not include any middleware primarily useful for browser applications (like cookies support) by default. *Make ApplicationController inherit from ActionController::API instead of ActionController::Base. As with middleware, this will leave out any Action Controller modules that provide functionalities primarily used by browser applications. *Configure the generators to skip generating views, helpers and assets when you generate a new resource.
```config.api_only = true````
- In config/application.rb for existing apps
```class ApplicationController < ActionController::API````