404 errors in PrestaShop: how to find them and fix them with 301s

A customer searches Google for the phone case they bought from your shop last year, clicks your result and lands on "Page not found". They don't look any further in your shop: they go back to Google and buy from the next one. That's a 404 error, and almost every PrestaShop shop has more of them than it thinks.

Here's where they come from, what they cost you, how to find them and how to redirect each one with a 301 redirect without touching any code.

Why do 404 errors appear in my PrestaShop shop?

A 404 is an address that used to exist and now leads nowhere. In a shop they almost always come from ordinary day-to-day changes:

• You delete a product you no longer sell. Its page disappears, but Google, the sites that linked to it and old emails keep sending people there.
• You change the name or URL of a product, category or page so it ranks better.
• You reorganise the catalogue: you merge two categories, drop a brand, close a section.
• You migrate to a new version or platform, and the new shop's addresses aren't the old ones.

What does a 404 cost me?

More than it seems, in three ways. The first is the customer: they arrive ready to buy and leave. The second is Google: when a page returns a 404 for a while, Google removes it from the results, and everything it had earned over the years goes with it. The third is links: if a blog or a comparison site linked to that product, that link no longer adds anything to your shop.

The good news is that it's fixed by sending each lost address to the page that best replaces it. That's a 301 redirect: it tells the browser and Google "this lives here now", and Google passes what the old page had on to the new one.

What does PrestaShop do out of the box?

Something. On a product page in the back office, in the SEO tab, you can choose what happens when you disable it: send visitors to another product or to a category. Since PrestaShop 9 the same exists for disabled categories. And if your shop's URLs include the product number, PrestaShop takes the old address to the new one by itself when you rename the product.

For everything else there's nothing: a deleted product always returns a 404, and content pages, brands, suppliers and any old address from a previous version of the shop have nowhere to be set up. Nor does it tell you which 404s are getting visits, which is exactly what you need to know to get started.

How do I find my shop's 404s?

In two places, and it pays to check both:

1. Search Console. Under "Indexing" → "Pages", the reason "Not found (404)" lists the addresses Google tried to visit and couldn't find. If your shop isn't set up there yet, start with that: we explain it in my shop does not appear on Google.
2. The shop's own log. Search Console only sees what Google sees. Visits that come from an old email, a link on another site or a bookmark don't show up there. For that, the shop itself has to record every 404 it receives, how many times and from where.

A tip so you don't lose the afternoon: sort by visits. A 404 with a hundred visits a month deserves a redirect today; one with a single visit from a bot, none at all.

301, 302 or 410? Which to use when

• 301, permanent. The usual case: the product no longer exists or has moved for good. Google transfers the ranking to the new page.
• 302, temporary. A product that's out of stock and coming back, or a campaign that lasts a few weeks. Google keeps the original address.
• 410, gone. A page that has no replacement. It tells Google to remove it as soon as possible instead of continuing to visit it.

Where do I redirect each page?

To the one that best replaces it for whoever arrives, and almost never to the home page. A deleted product goes to the one that replaces it or, if there isn't one, to its category; a category that disappears, to the closest one. Google treats a mass redirect to the home page as if it were a 404, and the customer looking for a specific case won't find it on the home page either.

And a trap you pay for later: if the redirect points to a URL typed by hand and one day you change that URL, the redirect returns a 404 again. The safe option is to point it at the product or category itself, so it keeps leading to its page even if it's renamed.

How do we handle it in our shops?

With our 301 redirects module for PrestaShop, which is free and works from PrestaShop 1.7.5 to 9. It records every 404 the shop receives, separates bots from people and, from each one, you create the redirect in a moment: to a product, a category, a page, a brand or any address. The rules point to the page itself, so they keep working even if you change its URL, and it doesn't touch the .htaccess file or the shop's code.

If your catalogue changes a lot, the PRO version does the rest on its own: it creates the redirect when you delete a product or change a URL, imports and exports rules as CSV and redirects addresses by pattern, which is handy when you're coming from another platform. And if you're going to upgrade PrestaShop from 1.7 to 9, install it first: from day one you'll see which old addresses are still getting visits.