HTTP Status Codes: What’s The Kazoo?

Sometimes when following search results from Google or while following a link from a site you encounter these messages. They have a code in them and you gape at it for a few seconds and then switch to other sites unable to discern any meaning from it.If you are the person that I just described then you have come to the right place.

So what are they? They are basically descriptions of states of HTTP communication. For those of you who don’t know, HTTP stands for HyperText Transfer Protocol which are the applicable rules that need to be followed for communication on the WWW (World Wide Web).

So what do those codes mean? What does it have to do with me? Were those codes left by my device to warn us about the end of the world?

Each status code is divided into subclasses based on the HTTP response provided to an HTTP request.

These classes are as follows:

• Informational (1xx)
• Successful (2xx)
• Redirect (3xx)
• Client error (4xx)
• Server error (5xx)

Informational (1xx)

So informational codes tell us about the status of HTTP communication and are provisional. These codes are usually never sent in response from a server as they were not included in the original draft of HTTP 1.0. This is for experimental purposes only. In other words if a server sends codes belonging to the 1xx series  you look over the shoulder for a Frankenstein monster. Don’t worry he is cuddly.

Successful (2xx)

Successful codes or codes from the 2xx series indicate successful processing of HTTP requests. When the 200 code means the request that you just sent was received. Then you get a 201 (created) code when the resource corresponding to fulfilment of your request has been created. If the process has started but not completed then you get 202 (Accepted) code. Ever been asked to do a project and you just hand someone else’s already completed projects in class? Yeah there’s a code for that too (203 Non-authoritative). Then there are the ones where process completes without returning anything (204 No content). 205 is the same thing only it will get the blank page.

Redirect (3xx)

3xx codes indicate that additional work needs to be done on the user’s part. Don’t worry it’s mostly the browser that does most of the work all the time. A most popular example of this is the 301 redirect. This code is used to redirect users to permanently shifted sites.

Client error (4xx)

4xx series codes mean that you have been typing into the PC with your feet while being blindfolded. You must be familiar with the famous 404 error. As you must know that this code appears when the page you are accessing does not exist. Other 4xx series codes are 400 (Bad syntax), 401 (Unauthorized), 403 (forbidden) are also known. Surprisingly enough there is a 418 (I’m a teapot) code which work for Hyper Text Coffee Pot Control Protocol. It was part of an April fool joke but some enterprising people actually implemented it.

Server error (5xx)

5xx codes signify that a server was self-destructed somewhere while processing your request. Don’t worry it’s not your fault. You must have seen occasional 500 internal error messages. These mean that the server failed due to an unknown error on its part. Other than this there are 501 (Request not recognized), 502 (bad gateway) and 504 (gateway timeout) codes. 502 and 504 occur in server acting as gateways. Gateways send requests to other servers for processing. If a 502 occurs the upstream server sent an error. If a 504 occurs it means that the gateway server waited too long for a response. Just like you were stood up on your date.

The codes explained in this article are a few of many status codes out there. Please leave your interesting comments by tweeting us at @letsnurture.