Application Layer The Missing Internet Stack **Overview of the Application Layer** The application layer is the highest layer of the Internet stack. It is responsible for providing users with access to the Internet and for running applications that communicate with each other. The application layer is made up of a variety of protocols, each of which is responsible for a specific type of communication. For example, the Hypertext Transfer Protocol (HTTP) is responsible for transferring web pages, while the Simple Mail Transfer Protocol (SMTP) is responsible for sending email.