404 error

You see a 404 error when you open an address the server can't find. The website itself is working, but the specific page doesn't exist (any more). That may be due to a typo in the link, a removed product or a page that has moved without a redirect. The visitor hits a dead end and often gives up.

Worth knowing: a 404 is not a disaster in itself. Every website that evolves runs into them sooner or later. Google itself says 404 pages are normal and don't penalise your website as a whole. The problem lies mainly in 404s in places where they don't belong: in your own menu, in your internal links or on pages that other websites link to.

How does a 404 error arise?

The causes are usually easy to trace:

• a page was removed without an alternative;
• a page's slug was changed, but old links still point to the previous address;
• no redirects were set up when launching a new website or switching to a different CMS;
• someone types or copies a link incorrectly, on your own site or on another website.

An example: a bike shop in Bristol removes old models from its online shop every season. The product pages disappear, but blog posts and forums still contain links to those models. Anyone who clicks on them gets an error message instead of the new model that closely resembles it.

What is the impact on SEO and AI search?

Search engines drop pages with a 404 from their index after a while. That makes sense: there is nothing to show. But if such a page had backlinks, their value is lost. On top of that, search engines waste time crawling broken links, which on large websites can come at the expense of your crawl budget.

AI search engines such as Perplexity or ChatGPT also link to sources. If a user lands on an error page via such a link, that is a missed opportunity and a poor first impression of your business.

How to tackle 404 errors

1. Map them out. In Google Search Console you can see which URLs Google registers as "not found". A crawler also shows broken internal links.
2. Decide what makes sense for each URL. If there is an equivalent page, set up a 301 redirect. If there really is no alternative, the 404 (or a 410) can stay.
3. Fix your internal links. Never link to a non-existent page from your own menus and text.
4. Create a helpful 404 page. Include a search function, links to your main categories and a clear message in your business's tone of voice.

A good 404 page is customer-friendly too

Do make sure your error page technically returns a genuine 404 status code. A page that shows "not found" but sends a 200 code confuses search engines. So the message is to check regularly, especially after a new website, a migration or a clean-up of your product range. A technical SEO analysis shows you where broken links and incorrect status codes are, so you can fix them in a targeted way.