HTTP or Hypertext Transfer Protocol is a protocol that governs how messages sent between two computers across the internet should be formatted and transmitted. HTTP messages are sent using TCP/IP. If you imagine HTTP as the writing in a letter, TCP/IP is the envelope.

HTTP is the primary protocol for transmission of information over the internet and a ubiquitous part of the internet. There is no competition with other protocols to do what it does. All servers on the internet conform to HTTP or it’s secure version HTTPS. You can type a URL in your browser as phoenixweb.com.au and most modern browsers will automatically append http to the front of the address to make http://phoenixweb.com.au.

Client Server Relationship

HTTP operates on the basis of one computer having a client relationship and another having a server relationship. The most common scenario for this relationship is your personal computer acting as the client and a computer hosting a website as the server. The client sends the server HTTP requests and the server replies with a HTTP response. If everything went to plan, there will be content in this response – usually a file.

Originally the only content sent via the HTTP protocol was HTML pages. This is what the HTTP protocol was designed for, hence the word Hypertext in both acronyms. These very words are part of a HTML page interpreted by your browser, and it was served to you via the HTTP protocol. Both HTTP and HTML were developed at CERN by the same team. Feel free to check out the first ever website, built by CERN, which is still online.

HTTP Response Codes

When a server sends a HTTP response, it sends a code to describe how it went. A common response is the 404 error, meaning the server couldn’t find what the client asked for in the HTTP response. A 500 error is another type of response denoting server failure. These responses are handy for troubleshooting problems with a website. Therefore if you are having problems with a web page and ask us for help, we are likely to ask for the HTTP response code.

Read More

Read more about HTTP at these resources:

• Webopedia HTTP definition ,
• NGinx website glossary HTTP entry
• ComputerHope HTTP definition