What is HTTP protocol? What are HTTP status codes?

The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. Wow!!! What a definition. Let me explain you in general terms.

We all communicate and to do that we follow a protocol or set of rules. In the same way, HTTP short for Hypertext Transfer Protocol is a set of standards that allow users of the World Wide Web to exchange information found on web pages. When wanting to access any web page enter http:// in front of the web address, which tells the browser to communicate over HTTP. For example, the full URL of my blog is http://performancetestingcentre.blogspot.com/

Status Codes

HTTP servers respond to client requests in the form of a response message. The first line of the HTTP response is called the status line and this includes a numeric status code as "500" and a textual reason phrase as "Internal Server Error".

These codes are mainly of five types:

Type 1: Informational - 1xx

Status Code	Meaning
100	Continue
101	Switching Protocols
102	Processing

Type 2: Success - 2xx

Status Code	Meaning
200	OK
201	Created
202	Accepted
203	Non-Authoritative Information
204	No Content
205	Reset Content
206	Partial Content
251	Fin (i-mail capture)
252	Rec (i-mail capture)
255	Empty (i-mail capture)

Type 3: Redirection - 3xx

Status Code	Meaning
300	Multiple Choices
301	Moved Permanently
302	Moved Temporarily
303	See Other
304	Not Modified
305	Use Proxy
307	Temporary Redirect

Type 4: Client Error - 4xx

Status Code	Meaning
400	Bad Request
401	Unauthorized
402	Payment Required
403	Forbidden
404	Not Found
405	Method Not Allowed
406	Not Acceptable
407	Proxy Authentication Required
408	Request Timeout
409	Conflict
410	Gone
411	Length Required
412	Precondition Failed
413	Request Entity Too Large
414	Request URL Too Large
415	Unsupported Media Type
416	Requested Range Not Satisfiable
417	Expectation Failed
451	ID Error (i-mail capture)

Type 5: Server Error - 5xx

Status Code	Meaning
500	Internal Server Error
501	Not Implemented
502	Bad Gateway
503	Service Unavailable
504	Gateway Timeout
505	HTTP Version Not Supported
552	POST Error (i-mail capture)
553	GET Error (i-mail capture)
554	Unordered (i-mail capture)
561	UE POST Error (i-mail capture)