Understanding the 404 error in SEO: definition and solutions

L'404 error is a response from web server which indicates that a resource requested is nowhere to be found.

In the field of natural referencing or SEO (Search Engine Optimisation), this error deserves particular attention so as not to have a negative impact on the visibility of a site on search engines such as Google.

Discover the precise definition of the 404 error, its impact on SEO and the best practices for avoiding or resolving it.

Why and how do 404 errors occur?

Before we start exploring the consequences of a 404 error on SEO, we need to understand how it works.

When a user or a indexing robot is trying to access a web page, it sends a request to the web server hosting the site. The server then has several HTTP response codes possible, some of which are error statuses.

The main HTTP error codes

400 Bad Request : Poorly formulated request.
401 Unauthorized : Unauthorised access to the resource.
403 Forbidden : Ban on access to the resource.
404 Not Found : Resource not found.
500 Internal Server Error : Internal server error.

The404 error appears when the server cannot find the requested resource, be it a page, an image or any other element of the site. There are several possible reasons for this:

Deletion of the page or content concerned
Change of URL without appropriate redirection
Bad hypertext link on a page
Typing error in the URL entered by the user

The impact of a 404 error on SEO

404 errors have a negative impact on theuser experience They cause disappointment and frustration, often leading visitors to leave the site. However, in addition to this direct effect, these errors can also have a detrimental effect on natural referencing.

The reputation of internal and external links

One of the important criteria for search engines is the quality and consistency of internal and external links. Links to pages that generate 404 error are considered as broken linksThis can have a negative impact on the ranking of a page and the site as a whole.

The dilution of link "juice

The " link juice PageRank" is a value assigned by search engines to each page, based on the links pointing to it and their quality. A 404 error can lead to a dilution of this link juice: if other sites point to a page that can no longer be found, the value of these links is lost for the benefit of your site.

Less efficient indexing

Finally, 404 errors can also have an effect on the capacity of indexing robots to explore a site. These robots have a limited "crawl budget", i.e. a maximum number of pages that they visit during an exploration session.

404 errors therefore increase the risk of certain pages being ignored by robots, reducing their visibility in search results.

How do you detect and correct 404 errors?

Fortunately, there are several solutions for identifying and resolving problems associated with 404 errors to preserve the integrity of its SEO.

Using search engine diagnostic tools

Google Search Console and Bing Webmaster Tools are two essential tools for monitoring the health of your site in relation to the main search engines. In particular, they allow you to consult the list of 404 errors detected by the indexing robots.

Use software to check for broken links

There is a wide range of software and plugins available to check for broken links on a website. These tools analyse all the pages and identify the 404 errorsmaking it easier to correct.

Setting up 301 redirects

When a page disappears or changes address, it is crucial to set up a 301 redirect. This automatically redirects the user to the new resource, preserving the user experience and conserving the link 'juice'.

Optimise your custom 404 error page

Lastly, not all 404 errors can be eliminated: they can also be caused by human error in data entry. URL. In such cases, it is advisable to create a special, attractive 404 error page, integrated into the site design and offering links to relevant content. This solution limits user frustration and encourages them to continue browsing your site.

To sum up404 error is a common but potentially damaging problem for SEO if not dealt with correctly.

Acting quickly to detect and resolve these errors is essential if you want to maintain the visibility, traffic and image of your site on search engines.