In this article
Key takeaways
- A redesign that changes page URLs loses SEO value unless every old URL is redirected.
- A 301 redirect tells Google the page has moved for good, so it can pass its signals to the new URL.
- The redirect plan is prepared before launch, from the complete list of old URLs.
- Each old page should point to its closest equivalent, not to the homepage.
- After launch, test the redirects and watch for 404 errors in Search Console.
A new website means a new design, often a new platform and almost always new page URLs. To Google, a URL that changes is a page that disappears, unless you tell it where the page went. That is the job of 301 redirects, and it is the step most often forgotten in a redesign.
A real case: 684 URLs returning 404 after a redesign
One of our clients, a Quebec company, had its website rebuilt by another team. After launch, 684 old URLs returned a 404, the “page not found” error. Overnight, that many addresses that visitors, external links and search engines could still use led nowhere.
The problem was not the new site itself, it was the move from the old one to the new one. It is exactly the question our clients ask us before a redesign: how do we keep what we have earned on Google?
Why a redesign loses SEO
Google ranks URLs, not companies. Over time, each page builds up signals: links pointing to it, a click history, a place in the index. When the URL changes without a redirect, the new page starts from zero and the old one returns a 404. Visitors who arrive through an old link land on an empty page, and Google eventually drops the old URL from its results.
AI answer engines are no exception. ChatGPT, Perplexity and AI Overviews cite specific pages. A cited page that falls into a 404 stops being a source.
What a 301 redirect does
A 301 redirect is a server response that says: “this page has moved permanently, here is its new address.” The browser follows automatically, and Google understands it should replace the old URL with the new one in its results. According to Google’s documentation on redirects, a permanent redirect is the strongest signal for which new URL to keep.
A 302 redirect is temporary: it says the old URL will come back. For a redesign, use a 301.
The redirect plan in 5 steps
1. List every old URL
Before touching the site, gather every existing URL: the sitemap, a full crawl of the old site, the pages that get traffic in Google Analytics, those with impressions in Search Console and those with external links. The sitemap alone is not enough, it often misses pages.
2. Match each old page to its equivalent
For each old URL, choose the new page that meets the same need: a service to the same service, an article to the same article. Redirecting everything to the homepage looks convenient, but Google may treat those redirects as missing pages (“soft 404s”) and pass nothing on. When a page truly has no equivalent, aim for the closest page, such as the category that contained it.
3. Avoid redirect chains
A chain is A redirecting to B, which redirects to C. Each hop slows loading and dilutes the signal. If the site already had redirects from an earlier redesign, update them so they point straight to the final destination.
4. Put the redirects in place before or at launch
Redirects must be live the moment the new site launches, not a week later. Depending on the platform, they are managed in a configuration file, a plugin or the CMS settings. Google’s guide to site moves with URL changes also says to keep them in place as long as possible, generally at least one year.
5. Test and monitor after launch
On launch day, test every old URL on the list: it should return a 301, then lead to a page that returns 200. In the following weeks, watch the “Pages” report in Search Console, under “Not found (404)”, to catch forgotten URLs. Submit the new sitemap as well.
The traps we see in the field
In the 684-URL case, two traps came up, and we see them often.
- The import that overwrites everything. On some platforms, such as Webflow, importing a redirect file replaces the entire existing list. The site already had redirects: we had to merge the old list with the new one before importing, or the old redirects would have been lost.
- Redirects saved, but not live. On those same platforms, a redirect only takes effect once the site is published. A saved list is not a live list: always test on the real domain.
When to call an agency
A small ten-page redesign can be handled by hand. As soon as a site has hundreds of URLs, external links, a store or several languages, the redirect plan becomes a project of its own. That is what our SEO migration and redesign service covers: the URL inventory, the mapping, the setup, the testing and the follow-up after launch.
Frequently asked questions
How long should 301 redirects stay in place?
Google recommends keeping them as long as possible, generally at least one year. In practice, we leave them in place as long as the old URLs still get visits or links.
Can I redirect every old page to the homepage?
It is not recommended. Google may treat a redirect to an unrelated page as a missing page, and the visitor does not find what they were looking for. Each old page should lead to its closest equivalent.
My site was already redesigned without redirects. Is it too late?
No. We recover the old URLs from Search Console, web archives and link tools, then put the missing redirects in place. The sooner it is done, the more signals you recover.