Why is the 404 error code called the 404 error code?

We’ve all fallen victim to the digital dead end. You’re aimlessly browsing the internet when, suddenly, the three dreaded digits appear like a virtual Gallic shrug: “404 Not Found”. To make matters worse, the error message is often accompanied by a cutesy cartoon or a skateboarding polar bear, making you want to throw your laptop across the room in despair. But what does the 404 error code actually mean? And why is it the four hundred and fourth?

There is a story – most likely nonsense – that the original database for the world wide web, as developed by those CERN chaps, was placed in room 404. The idea is that the original message was “Room 404: Not Found”, meaning the search didn’t find the database. As we say, most likely nonsense.

The 404 error code makes more sense when you consider that it’s one of the Hypertext Transfer Protocol (HTTP) standard response codes – think of them as a tracking system for your browsing. The codes are divided into five categories and the fourth deals with problems caused by the client. Helpfully, these codes all begin with a “4” and include such gems as:

• 400 Bad Request. The server can’t process a request because of a client error.
• 401 Unauthorized. Essentially, this means you don’t have the right credentials to visit a site. So get out. Now.
• 403 Forbidden. If you see this, your request was valid, but, like a nightclub bouncer, the server doesn’t like it. You might need to make an account or get permission to enter.
• 408 Request Timeout. This means you haven’t been quick enough on the draw and your request is no longer valid. Boo hoo.
• 410 Gone. One of the starker error codes, this will show when the resource is gone and will never come back.

Our friend “404 Not Found” fits neatly into this family and means the requested resources can’t be found, but may be available again in the future. It’s most commonly encountered when you come across a broken or dead link, such as a very old news story that has been deleted or a page that has been moved.

However, in the unlikely event you confronted by a 404 error code on The Big Tech Question, brace yourself…

Have you got a burning tech question you’d like to ask? Then ask us via Twitter or using our online form.