The HTTP protocol, which stands for “HyperText Transfer Protocol” is a communication protocol that determines the rules between the client (web browser) and the server and enables the viewing of webpages over the network. The HTTP protocol was first used in 1990.
What are HTTP Status Codes?
HTTP status codes indicate whether a request sent from the web browser to the web server was successful or unsuccessful. Usually, users may not see these codes in the browser, but status codes are returned to the client in HTTP headers each time the web browser communicates with the server.
HTTP error and status codes are essential for healthy web development and a good user experience. Also, the status codes are important for SEO. If you have many pages with HTTP errors, it may negatively affect your website on search engines. Also, if you have irregular redirects on your website, search engines may list these pages that you don’t want instead of the ones you want.
Not every HTTP status code indicates an error. Some codes are informational; some indicate that the webpage loads without any problem or an error. You will learn the common HTTP status codes after reading this article.
HTTP status codes can be grouped into five classes: Informational, Successful, Redirect, Client Error, and Server Error.
Informational HTTP Status Codes: 100-199
1xx HTTP status codes indicate that the request sent by the web browser continues to be processed on the server side.
What is HTTP 100 (Continue)?
HTTP 100 status code means that the request was received successfully and can be continued.
What is HTTP 101 (Switching Protocol)?
HTTP 101 status code means that the server states that it will comply with the protocol change request it receives from the client.
What is HTTP 102 (Processing WebDAV)?
HTTP 102 status code means that the server has received the request and is processing it but has not yet responded.
Successful HTTP Status Codes: 200-299
2xx HTTP status codes indicate that the web browser’s request to the server was successful, and the webpage can be loaded without any problems.
What is HTTP 200 (OK)?
HTTP 200 status code means that the request was successful.
What is HTTP 201 (Created)?
HTTP 201 status code means that the request was successful, and a new page/resource was created on the server.
What is HTTP 202 (Accepted)?
HTTP 202 status code means that the server accepted the request and has not yet processed it.
What is HTTP 203 (Non-Authoritative Information)?
HTTP 203 status code means that the server processed the request successfully but is returning information that may be from another source.
What is HTTP 204 (No Content)?
HTTP 204 status code means that the request was received successfully, but the content is not returned.
What is HTTP 205 (Reset Content)?
HTTP 205 status code means that the request was received successfully, but the content is not returned. However, the content will be cleared (for example, information filled in a web form).
Redirect HTTP Status Codes: 300-399
3xx HTTP status codes inform the web browser that the page/resource requested from the web server has been redirected to a different page/resource.
What is HTTP 300 (Multiple Choice)?
HTTP 300 status code means more than one option available on the server. The server can select the option itself or display the options list.
What is HTTP 301 (Moved Permanently)?
HTTP 301 status code means that the requested page/resource was permanently redirected to another URL.
What is HTTP 302 (Found)?
HTTP 302 status code means that the requested page/resource was temporarily redirected to a different URL.
What is HTTP 303 (See Other)?
HTTP 303 status code means that a GET request should be made to a different page/resource.
What is HTTP 304 (Not Modified)?
HTTP 304 status code means that on the requested page/resource, it is stated that there has been no change since the previous request, and the content is not sent.
What is HTTP 307 (Temporary Redirect)?
HTTP 307 works the same as 302. The difference is the 307 code tells the client to request the original URL the next time. It can also be called a one-time redirect code.
HTTP Client Error Codes: 400-499
4xx HTTP status codes indicate that a client-side error has occurred and that the requested page/resource is not found on the server, cannot be accessed, or access is blocked.
What is HTTP 400 (Bad Request)?
HTTP 400 status code means that the request or the structure of the request is incorrect.
What is HTTP 401 (Unauthorized)?
HTTP 401 status code means that the request requires authentication.
What is HTTP (403 Forbidden)?
HTTP 403 status code means that the page/resource is forbidden.
What is HTTP (404 Not Found)?
HTTP 404 status code means that the requested page/resource could not be found.
What is HTTP 405 (Method Not Allowed)?
HTTP 405 status code means that the server does not accept HTTP Method.
What is HTTP 410 (Gone)?
HTTP 410 status code means that the page/resource was deleted and no longer exists.
What is HTTP 429 (Too Many Requests)?
HTTP 429 status code means that the requests made by the client to the website are more than the limit set by the software.
HTTP Server Error Codes: 500-599
5xx HTTP status codes indicate that a server-side error has occurred and the requested server cannot be accessed.
What is HTTP 500 (Internal Server Error)?
HTTP 500 status code means that an error occurred on the server, and the request could not be fulfilled.
What is HTTP 501 (Not Implemented)?
HTTP 501 status code means that the server is not configured to fulfill the requested request.
What is HTTP 502 (Bad Gateway)?
HTTP 502 status code means that Gateway or Proxy server cannot receive a response from the server (upstream server) where the page/resource is located.
What is HTTP 503 (Service Unavailable)?
HTTP 503 status code means that the server is currently down (down or unreachable). More information: What is HTTP 503 Error?
What is HTTP 504 (Gateway Timeout)?
HTTP 504 status code means that the Gateway or Proxy server did not receive a response from the server where the page/resource is located (upstream server) within a specific time.
What is the difference between HTTP 4xx and 5xx?
The difference between 4xx and 5xx status codes is that 4xx status codes indicate that the error has occurred on the client-side, 5xx status codes indicate that the error has occurred on the server side.
What is the difference between HTTP 200 and 201?
200 status code indicates that the request was successful, 201 status code indicates that the request was successful and as a result, a resource has been created (for example, a new page).
What is the difference between HTTP 302 and 307?
The difference between 302 and 307 is 307 code tells the client to request the original URL the next time. It can also be called a one-time redirect code. Also, another difference from other HTTP redirect status codes is that the browser will make the request with all HTTP headers and parameters (body). 301 and 302 codes do not do this; only redirection takes place.
Importance of HTTP status codes for SEO
Search engines also consider HTTP status codes when crawling web pages. Depending on the type of status code, they can perform operations such as a successful load, redirect, or deletion of faulty pages from the index. We can redirect the pages manually by giving the proper signal to the search engines by providing the HTTP status code.
Sometimes we may have to delete or redirect a page. It is possible to notify search engines that the page has been deleted or redirected to another page using HTTP status codes.
In addition, your pages with 4xx and 5xx status codes can create fatal consequences for your website’s SEO efforts.
How can you use HTTP 3xx codes for SEO?
When you move a page to another URL, you must notify the search engines. Otherwise, the old URL will return a 404 code and confuse. When you use the HTTP 301 code the old URL to the new URL, the search engine bots will understand this, remove the old URL from the index, and redirect the page to the new URL with all its backlinks and ranks.
How to fix HTTP 4xx error codes for SEO?
You should detect your pages that respond to HTTP 404 (Not found) and redirect them to a relevant page using HTTP 301 (Moved Permanently). If you don’t have a page to redirect, you can inform the search engines that “this page has been completely deleted” by using the HTTP 410 (Gone) code.
How to fix HTTP 5xx error codes for SEO?
5xx status codes mean that the page cannot be accessed due to an error on the server. This could be due to a flaw in the server configuration or your site’s code structure. You should immediately identify the cause and fix the problem.
How to check the HTTP status code of a webpage/resource?
You can use httpstatus.io to check the HTTP status code of the single or multiple URLs easily. Enter URLs to check, one per line, then click the Check Status button.
2. Link Redirect Trace Extension
The second way to check HTTP status codes is the Link Redirect Trace extension. This extension is available on Chrome and Firefox browsers. To see the status code of a web page, just click the extension icon at the top of the web browser.
- Download for Chrome: https://chrome.google.com/webstore/detail/link-redirect-trace/nnpljppamoaalgkieeciijbcccohlpoh
- Download for Firefox: https://addons.mozilla.org/en-US/firefox/addon/link-redirect-trace-addon/