How-to 9 min read

How to check and adjust the server response codes

With every accessing to the page of the website, user or a robot of the search engine makes a URL query. After that, the server gives out a three-digit number - which influences the final outcome. During the optimization, it is important to know which response codes exist and how to correctly adjust them.

What does the server response code influence

With a successful file event, user receives the correct site in the browser, a web robot based on the received data starts scanning its content. A correct server status leads to a fast page indexation, which is an important aspect for SEO.

The necessity to adjust the HTTP-codes appears with changes on the website. For example, disposal of pages, transition to a new CMS, change of URL-addresses. In this case, a webmaster can use the code correction for controlling the search engine indexation and successful redirection from one page to another.

Classification and difference of answer codes

Server answer is a three-digit code and a short explanation in the form of a text. To check the server answer and orientation in the codes was comfortable, they are divided into state classes. Classes differ the first number of their three-digit code - from 1 to 5. Every group of codes has its special features

Information codes. Codes, starting on 1, tell about the successful query receive and start of the process of data transaction. Example: 102 Processing.

Successful completion of the query.
If the server status check shows a code, the first number of which is a 2 - it is a signal about the positive server answer in the browser and for the web robots. Example: 200 OK.

Redirection codes. Server HTTP-answers, which start on 3, are in charge of redirection. They are used for successful navigation between URL. Example: 301 Moved Permanently.

HTTP-bug codes. 4 and 5 are class markers, which signalize about bugs on the user's side or malfunctions in the server functionality. Example: 404 Not Found, 500 Internal Server Error.
500 Internal Server Error

Widely-spread server response codes

Let's highlight the main server signals and appropriate codes for them.

200 OK

A page with 200 OK code says about the successful query processing. This means that the user saw the needed page on the screen and a web robot received an opportunity to indexate it. All pages important for promotion need to have a 200 status.

301 Moved Permanently

Redirection code means that page's URL is changed. Adjustment of the 301 redirect allows to transfer a page from one address to another, saving all the built-up link mass. For example, during the movement onto a new platform. Also, answer 301 is used during the adjustment of the website's mirror.
Server code 301 Moved Permanently

302 Found

Answer 302 differs from the previous one in an aspect that it is used only during a temporary transfer of a URL or document. In this case, the page is left in the index.

304 Not Modified

Code 304 is not a bug. This server answer says that there weren't any updates on the quoted page since its last visit. It is a signal that there is no necessity in its reprocessing. Getting the 304 code, the search engine does not index the page again, but goes to the updated data, which, all in all, speeds up the site scanning process.

403 Forbidden

This bug code says about the prohibition to see the content of the website. It can be seen, when the user got an access denial, for example, during the IP-address restrictions or in an attempt to see the system files of the site. If the prohibition is contingent on the bridge of legislation or author's rights on the content, in this case the error will be reset with the code 451 Unavailable For Legal Reasons.

404 Not Found

404 status appears on the screen, if the server did not find any information on the URL - the quoted page does not exist. This often happens, when the page of the web-resource is deleted. It is important, that the server gave out a 404 code when referring to missing pages. It is necessary to:

  • stop the indexation of deleted pages by the robot;
  • exclude the 200 answer and unneeded content duplication.
Error 404 Not Found

410 Gone

If an answer 404 informs that the page is missing, but in itself is not deleted and can be restored (or created) later on, then status 410 can be applied to completely deleted pages. Receiving a signal with the 410 code, web robot stops the scanning of this page.

422 Unprocessable Entity

Bug 422 informs, that the server understands the content type in the query, but cannot process it because of a logic error. This answer code is displayed, for example, if there is an XML-document in the query with the correct syntax, but semantically incorrect instructions.

500 Internal Server Error

Code says about the unavailability to process the query because of malfunctions on the server. Often, this problem is conditioned as an incorrect syntax of the configuration file htaccess, and the problem can be solved by editing its guidelines. Also, this status can appear because of incorrect use of CGI-scripts for connection of an exterior program with the server.

503 Service Unavailable

Server is temporarily unavailable. Procession of queries is stopped because of technical changes, for example, because of its overload or slow connection with the database. Also, the server can be overloaded and not cope with a huge amount of requests to the site.

This code can also be used when the server is under maintenance. Web robot will receive the needed signal and analyze the pages later.

504 Gateway Timeout

This bug can be seen, when server carries the function of a gateway or proxy-server. 504 code says about the missing data from the main server during the query completion.

How to find out server statuses for website pages

What can help you to find out the HTTP status codes?

Browser options and special apps. Code value is in the Status column in the worksheet Network in Google Chrome.

To get this data, you have to open the needed page of the site in the browser, then press F12 to activate the webmaster's functional board.

Also, in the browser you can download the plugin Redirect Path.

Free resource for diagnosing the answer codes is the analysis of one page or complex scanning of a few of them at the same time.
Server answer check online

How to adjust the server response codes

To change the server answer status, you should work with HTTP-heading in the php-file of the page. Depending on the task, header in the body of the delineated document function can look like this.

Successful site answer to the query:
header('HTTP/1.1 200 OK');
Quoted page does not exist:
header('HTTP/1.1 404 Not Found');
The page was redirected:
header('HTTP/1.1 301 Moved Permanently');
Redirect to an actual URL:
header('Location: http://mysite.com/');


Server response codes influence the final look of the page in the user's browser and are an instruction for web robots. Code diagnosis, which recovers the pages of the websites as an answer to the query, allows to uncover the weak spots of the optimization.

With the help of a correct status adjustment, you can give the needed signal to the search engine, influence the process of site indexation and complete an effective page redirection.

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