HTTP is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of upstream servers to improve response time.
Basically, HTTP is an TCP/IP based communication protocol, which is used to deliver data (HTML files, image files, query results etc) on the World Wide Web. The default port is TCP 80, but other ports can be used. It provides a standardized way for computers to communicate with each other.
HTTP is the protocol behind nearly all communication on the web. A browser loading a page sends an HTTP request for the HTML document, parses the response, then sends additional requests for stylesheets, scripts, images, fonts, and other subresources.
Hypertext Transfer Protocol (usually abbreviated to HTTP) is a communications protocol. It is used to send and receive webpages and files on the internet. It was developed by Tim Berners-Lee and is now coordinated by the W3C. HTTP/1.1 is the most-used version today, and RFC 2616 completely explains how it should work.
Now that both HTTP extensions and HTTP/1.1 are stable specifications (RFC2616 at that time), W3C has closed the HTTP Activity. An effort to revise HTTP/1.1 started in 2006, which led to the creation of the IETF httpbis Working Group. Work completed with the publication of RFC 723X (See below)
HTTP is an application-layer protocol for transmitting hypermedia documents, such as HTML. It was designed for communication between web browsers and web servers, but it can also be used for other purposes, such as machine-to-machine communication, programmatic access to APIs, and more.