In earlier days, the term serverless referred to an application that was dependent on third-party applications or services to manage server-side logic. Such applications were cloud-based databases, such as Google Firebase, or authentication services, such as Auth0 or AWS Cognito. They were referred to as Backend as a Service (BaaS) services. But serverless also means code that is developed to be event-triggered, and which is executed in stateless compute containers. This architecture is popularly known as Function as a Service (FaaS). Let's look at each type of service in a bit more detail.