Serverless architecture, often simply called 'serverless', is a cloud-computing execution model where the cloud provider dynamically manages the allocation and provisioning of servers. In this model, developers are not concerned with server management tasks; instead, they focus purely on individual functions in their application code.
It's called 'serverless' because the developers do not have to purchase, rent, or maintain servers for the back-end of their applications. The server management is done automatically by the cloud provider. This does not mean there are no servers involved, but simply that it's the cloud provider's responsibility to manage the servers.
The serverless architecture is event-driven, meaning applications are built based on the reaction to a series of events. This provides developers with high flexibility and the ability to scale automatically.