CloudKit

- The document discusses the CloudKit framework, which allows building RESTful web applications and services using Rack, HTTP, and JSON. - CloudKit exposes collections of JSON documents through a RESTful interface and handles common tasks like content negotiation, versioning, and concurrency control using HTTP features like ETags. - Examples are given of creating, retrieving, updating and deleting resources representing todo items using CloudKit and making HTTP requests with curl. This allows building a basic RESTful todo application within a few lines of code.