The tutorial covers the use of Couchbase Lite in a React Native application, including creating a database, persisting documents locally, using Sync Gateway for bi-directional synchronization and server-side user authentication. The code is written in JavaScript and uses the React Native framework to build a simple Todo application with multiple users. The tutorial includes step-by-step instructions and explanations of key concepts such as Couchbase Views, replications, and design documents. It also provides a starter project that can be used as a basis for building more complex applications.