GraphQL is a powerful query language for accessing data stored in backend systems, allowing developers to fetch and manipulate data through an HTTP API. The examples in this tutorial show how to write a GraphQL query using various programming languages such as cURL, Python, PHP, JavaScript, Ruby, Java, and Postman, and demonstrate how to use these queries to retrieve data from a simple employee database schema. The tutorial also provides information on how to use the GraphQL Playground tool for Contentful users to start learning GraphQL right in their browser.