Ratpack, a set of Java libraries for building modern HTTP applications, is highlighted in this text as a non-blocking, asynchronous framework that integrates well with Couchbase's Java SDK for document databases. The author explains how to set up a basic Ratpack application using Java, outlining the process of creating a simple CRUD API, starting with a "Hello World" example. Ratpack's core concept of handlers, which are functions associated with paths, is discussed, alongside the entry point for applications, the RatpackServer class. The text further delves into the implementation of Couchbase's entity model, demonstrating how to define and manipulate entities using annotations like @Id and @Field, and how to handle blocking code using Ratpack's asynchronous tools like Promise and Blocking. The author provides examples of creating and retrieving user data through HTTP paths, emphasizing the potential for Ratpack to facilitate the migration of existing applications to a more asynchronous model. Future posts are promised to explore the integration of RxJava with Ratpack for enhanced asynchronous capabilities.