What is HTTP ?

HTTP (Hypertext Transfer Protocol) is a protocol for data transmission with a network. It is mainly used, to load websites and other data from the World Wide Web (WWW) in web browsers.

HTTP belongs to the application layer of established network models. The application layer is called up by an application program; for HTTP this is usually a web browser. In the ISO/OSI security model it is the application layer of layer 7. TCP/IP, the reference model used on the Internet, sees the application layer in layer 4.

HTTP is basically a stateless protocol. This means that after data is transmitted, the connection between partners need not be maintained. If further data needs to be transmitted, a new connection must be made. Reliable logging of session data can be implemented by cookies, for example, in the application layer.

Due to expansion of request methods, header information, and status codes, HTTP is not restricted to Hypertext, but can also be used to exchange data. HTTP is a reliable transportation protocol for communication. In almost all cases TCP is used.

It was developed in 1989 by Tim Berners-Lee at CERN along with the URL and HTML, which was basically the birth of the World Wide Web (WWW).