Two of the most critical structures within web application development are requests and responses. As with most other programs, a web application needs to take inputs, and produce outputs. As HTTP is a stateless protocol, each request made will result in a response message back to the caller. For a web application, the input comes in the form of an HTTP request, and the output as an HTTP response. The net/http package contains data structures that completely model the HTTP protocol message types, which are used by most of the many web frameworks built with Go. In the following diagram, you can see the HTTP request and response protocol data structures: