What is a 404 Error?

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What is a 404 Error?

What is a 404 Error?

The 404 Not Found status code indicates that a server has unable to find the requested resource. This code is commonly used when a page or resource is missing, deleted or never existed.

What does 404 Not Found mean?

When a server responds with a 404 Not Found status code, it means:

  • The requested URL is incorrect or has been removed.
  • The requested resource does not exist on the server.
  • The server is unable to find the requested resource.

How is 404 Not Found different from 200 OK?

A 200 OK status code indicates that a request was successfully processed, and the result is available. In contrast, 404 Not Found indicates that the requested resource is not available.

When is 404 Not Found used?

The 404 Not Found status code is commonly used in the following scenarios:

  • Page not found: When a user requests a page that does not exist.
  • Resource not found: When a requested resource, such as an image or file, is not available.
  • Broken links: When a link is broken or the destination page has been removed.

Best practices for using 404 Not Found

Here are some recommended best practices for 404 pages

  • Customize 404 error pages to provide a better user experience.
  • Provide clear instructions on what to do next.
  • Use search engine friendly practices to help search engines understand the error.

Notes From Googlers

404 (Not found) errors are not to be afraid of and you don’t need to scramble to fix them, at least not most of the time.

A HTTP 404 status code is for cases when a URL on your server is not mapped to a resource, so from your perspective it can be one of these two buckets: the URL SHOULD return content and a 200 status code, or the URL was indeed not supposed to return content. This second bucket could be split further, specifically URLs that could be useful to users and URLs that are absolutely useless. So we have:

1. the URL SHOULD return content and a 200 status code. For example, you accidentally deleted the HTML mapped to the URL, or you messed up something with your database.
You should fix these as soon as possible, especially if the URL is important to your users and thus site.

2. the URL was indeed not supposed to return content, which can be either
a) the URL COULD be useful to users. You should probably think about mapping these URLs somehow to a piece of content on your site by eg. redirecting. Some cases I’ve seen that fall into this category are broken links from high user-traffic pages; the users tap on the link, they find a 404 error even though you have the perfect content for them.
b) the URL is absolutely useless. From a user’s perspective, there’s nothing you should do about these. If you do, you just mislead them. Some cases I’ve seen that fall into this category is off-site links to content that you don’t have (say you changed business and you don’t sell surströmming anymore).

Unconventional as it may be, you don’t need to fix all 404 errors: fix those that actually will help users.

Gary Illyes

More citations on how to remedy 404 pages

Staying on the 404 (Not found) topic, try to not call expensive backend functions/methods on your custom 404 pages unless it’s worth it.

After your site grows a bit, you’re likely gonna get a lot 404 errors. Broken links, while harmless from Google Search’s perspective, can cause quite some headaches if your 404 page is expensive to create by the server.

Let’s say that, due to some database scans, to fill a carousel with alternative product suggestions costs 1% of the total available resources of the server, like RAM and CPU. That means that if there are 100 clients (users, crawlers, etc.) on your site accessing 404 pages with that carousel at roughly the same time, they’re exhausting all the server’s resources. No resources left means the server will either refuse to make new connections or will throw some sort of error to new clients. Either way, you’re missing out on conversions.

So what can you do? Make it a marketing issue: you need to figure out how much your custom 404 pages are worth to your business and your users. Can they convert on your 404 pages? If not, can you actually make them convert?
If yes, redesign and re-redesign your 404 page until the conversion rate is acceptable for your business (in relation to the server resources spent on the 404s).
If no, make the 404 page simpler so it’s cheap enough to create that you don’t have to care about them. Put some JS game, a meme, or a doggo on the page, and forget about it.

If you need some inspiration, I found the examples in this article by AnnaLea Crowe quite entertaining: https://lnkd.in/g-XkPJPa (please tag them if you’re a better LinkedIn searcher than I am). I found it especially interesting that the example pages in that article don’t seem to be server resources heavy, so maybe 404s don’t generally convert well.

Gary Illyes