Backend as a Service (BaaS) is a cloud computing service model that provides developers with a ready-made backend infrastructure for their applications. This allows them to focus on building the frontend and user experience without worrying about server management, database maintenance, or other backend tasks. BaaS typically includes features like user authentication, data storage, and push notifications. By using BaaS, developers can save time and resources, as they do not need to set up and maintain their own servers. Popular BaaS providers include Firebase, AWS Amplify, and Parse, which offer various tools and services to streamline app development.