This tutorial covers building a GraphQL server using Apollo Server, with the goal of connecting to multiple backends such as SQL databases and MongoDB. The server is built using Node.js and npm packages like Sequelize for the SQL database connection and mongoose for the MongoDB connection. The resolvers are used to define how data should be retrieved from each backend, and caching is set up to improve query performance. The tutorial covers various aspects of building a GraphQL server, including setting up tracing, connecting to REST endpoints, and configuring caching. It also includes an example of using Apollo Engine for server-side caching. Overall, this tutorial provides a comprehensive guide to building a GraphQL server with multiple backends.