RapidAPI has launched RapidQL, an open-source project designed to simplify data aggregation from multiple APIs and databases using a single query language, enhancing ease for developers building complex queries. The tutorial demonstrates creating an application that retrieves user data from a MySQL database, fetches weather information via the Open Weather Map API, and sends a text message with this data using Twilio's SMS service. RapidQL allows for seamless integration of multiple data sources, including database queries and API requests, offering features such as default parameter settings and response flattening to tailor the output. This integration streamlines the process of fetching and combining data, illustrating RapidQL's potential in various applications.