The application layer forms the seventh layer/Layer 7 in the OSI model, the standardized reference model for structuring network communication.
This layer provides functions, services and interfaces for applications to access network resources. It also handles file input and data output. The main task of this layer is to enable communication between applications on different end systems. The layer thus establishes the connection to the lower layers of the OSI model. Examples of applications in this layer are web browsers, e-mail clients, FTP clients (File Transfer Protocol) and many other programs that use network services.
The application layer therefore plays a crucial role in providing interfaces for interaction between users and networks.