With cloud computing and the advent of microservices, BaaS started to gain momentum as well. BaaS systems are those that provide infrastructure software services, and these include storage as a service, database as a service, messaging, and notifications as a service. With serverless architecture, applications usually use a combination of BaaS services, which are often provided by the vendor cloud echo system such as Google's Firebase and Amazon DynamoDB. Other third-party BaaS services may include authentication services (like Auth0, AWS Cognito, and Azure Active Directory).
There are different strategies where some organizations decide to use a rich frontend app talking directly to the database as a service, for example (which some also call stored procedure as a service), and other organizations still prefer to have a thin version of middle-tier API backend services in the middle of the frontend and the BaaS.