HTTP means HyperText Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web. Developed by Tim Berners-Lee, HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands.
For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page. The other main standard that controls how the World Wide Web works is HTML, which covers how Web pages are formatted and displayed.
Recommended Reading: Webopedia’s HTTP response header and HTTP request header definitions.
HTTP is a Stateless Protocol
HTTP Status Codes are Error Messages
Errors on the Internet can be quite frustrating — especially if you do not know the difference between a 404 error and a 502 error. These error messages, also called HTTP status codes are response codes given by Web servers and help identify the cause of the problem.
For example, “404 File Not Found” is a common status code. It means the Web server cannot find the file you requested. This means the webpage or other document you tried to load in your Web browser has either been moved or deleted, or you entered the wrong URL or document name.
Knowing the meaning of the status code can help you figure out what went wrong. On a 404 error, for example, you could look at the URL to see if a word looks misspelled, then correct it and try it again. If that doesn’t work, backtrack by deleting information between each backslash, until you come to a page on that site that isn’t a 404. From there you may be able to find the page you’re looking for.