Every time you click on a link or enter a URL of website into the address bar, you are sending a request to the server. It doesn’t matter, you start with shared web hosting or something different, it processes it and generates a response in which the initial part shows the server status code.
The server response code (or HTTP status code) is the first three digits and a phrase in English that make it clear to the user (browser), crawler and search robot how the site responded to a request for a particular page or document. For example, the page response code 200 OK speaks for itself: “Everything is OK, you have reached the right address.”
HTTP status codes
1xx is an information class that the client needs when working with data transmission or processing. Most of them are official and are rarely seen in everyday work.
2xx – HTTP code that indicates the successful processing of the request by the server.
3xx – the three hundredth code indicates a redirection of the request from one address to another. By the way, newcomers to SEO are most worried about exactly what kind of redirect to put. So we’ll come back to this issue.
4xx is a status code that indicates an error on the user’s side. The reason for the error is explained by the phrase after the three digits of the code.
5xx is also an error code, but in this case it occurred on the server side. The reasons vary, but as with the fourth class codes, the reason is always described after the code number: sometimes it indicates high load, sometimes it indicates internal errors on the server.
Ways to check the server response code
There are many ways to check the server response code of a company: the developer toolbar in the browser ( F12 + Network tab), browser plugins, special online services, various SEO services. But I still work for Netpeak Software, so I’ll show you how to do it with our Netpeak Spider tool.
Registered, downloaded Netpeak Launcher, installed Netpeak Spider, launched it. Then there is a choice depending on your tasks:
- Checking the response of the server code on all pages of your site;
- Bulk check of the server response code against the list of pages.
A response that indicates a successfully processed request: the server gave a response → the page was found → the information was transferred to the client.
301 Moved Permanently
The requested document has been moved to another URL permanently.
This is the server response code that causes the most questions for beginners. In fact, the answer is simple: all pages from which users need to be permanently redirected to another page (duplicates, deleted pages, mirrors, and all sorts of things that you won’t tell Google about in confession) should respond with this code.
After crawling such pages, search engines will sooner or later “glue” them to the redirect landing page and pass on the link juice. And, of course, try to remove all links to pages inside the site that give 301 response codes, and put down the redirect landing page right away.
A code that indicates that the user has not yet been authenticated, or the data is incorrect.
Access is denied. The server has received the request, but is refusing to fulfill it due to access restrictions (for example, when the user wants to view system files or other documents to which he does not have access).
404 Not Found
Nothing was found at the address the client contacted. Be sure to set up this answer on your site for non-existent pages, because search engines may index such pages incorrectly, and you will get a whole list of them in the SERP.
500 Internal Server Error
The error indicates that the server cannot process the request. This is any unexpected situation for the server, the cause of which he is not able to determine (it does not correspond to any other five-hundredth error).
503 Service Unavailable
The server is unavailable and requests are temporarily unavailable for technical reasons. The most common response you see is when the server is under maintenance or overloaded.
All in all
Finally, let’s go over everything that has already been said: The server response code is three numbers and a phrase in English that make it clear to the user (browser), crawler and search robot how the site responded to a request for a specific page or document.