Website migration without losing SEO: how to keep your traffic

The new website went live on a Monday. It was faster, better looking and far easier to edit. Three weeks later the sales director calls: enquiries through the website have almost halved. It turns out the page for the company’s most important service, which had ranked first on Google for years, has a new address, and the old address now shows an error page. The same goes for 60 blog posts and all the product pages. Nobody did anything wrong on purpose. There simply was no plan for the migration. The good news is that the plan is fairly simple to make once you know what it must contain.

Why do websites lose traffic after a migration?

Google has spent years getting to know your old site. Each address has built up rankings, and many have earned links from other websites. When addresses change without notice, Google starts over with the new pages, and the value of the old ones disappears. These are the most common causes of traffic drops we see:

• Old addresses return a 404 error, because no redirect forwards them to the new page.
• Every old address is sent to the homepage, which Google often treats as an error page.
• Content that ranked has been deleted or cut down during the redesign.
• Titles, headings and descriptions have changed or are missing on the new pages.
• The site launched with a "noindex" setting or a robots.txt from the test environment that blocks Google.
• Internal links and the menu no longer point to the most important pages.
• The new site is slower or has problems on mobile.
• Structured data, hreflang for language versions, or the sitemap has disappeared.

Which types of migration are there, and how risky are they?

A good rule is to change as little as possible at once. If you need a new platform, a new design and a new domain, consider doing the domain separately, so you can see what affects what. If the addresses can be kept on the new platform, that is often the cheapest insurance you can buy.

How do you build a redirect map?

A redirect map is a spreadsheet with two columns: the old address and the new address it should forward to. It sounds trivial, but it is the document that decides whether the migration succeeds. Here is how to build it:

1. Collect every old address: crawl the old site with a tool such as Screaming Frog, and fetch the sitemap.
2. Export the pages that have had impressions and clicks in Google Search Console over the last 12–16 months.
3. Add the pages that get traffic in your analytics tool and those that have links from other websites.
4. Find the closest new page for every old address: same topic, same purpose.
5. Give pages without a counterpart a redirect to the most relevant category or parent page.
6. Check that no redirect points to another redirect, so you avoid chains.
7. Test the whole list automatically on the staging environment before launch, and again on launch day.

What should you check before the new website goes live?

• The redirect map is finished, reviewed and tested on staging.
• Every important page has a title, a description and one clear H1.
• The content on pages that rank today is preserved or improved.
• Internal links and the menu point directly to the new addresses, bypassing redirects.
• The sitemap has been generated with the new addresses.
• Canonical tags point to the correct version of each page.
• Hreflang is set up between language versions if you have several languages.
• Structured data (such as organisation, products, FAQ) has been carried over.
• Analytics and conversion tracking are set up and tested.
• The site passes Core Web Vitals on mobile.
• There is a plan for who removes the search-engine block on launch day.

The speed point deserves attention, because a new site that is slower than the old one can cost rankings even with perfect redirects. See the thresholds in our guide to website speed. For the launch itself, beyond SEO, we have a broader website launch checklist.

What needs to happen on launch day?

What should you watch in Search Console after the migration?

Google Search Console is your most important tool for the first three months. Set aside a fixed time each week to go through these reports, and compare with the period before launch:

• Pages: is the number of indexed new pages rising, and are the old ones dropping out in step?
• Not found (404): are old addresses showing up that are missing from the redirect map?
• Performance: compare clicks and impressions for the key search terms with the same weeks before launch.
• Sitemaps: has the new sitemap been read without errors?
• Core Web Vitals: is the new site green on mobile once field data comes in?
• Links: are external links starting to be registered on the new addresses?

How long until traffic recovers?

With a well-planned migration of a typical business site, we most often see fluctuations for two to six weeks while Google revisits the pages and moves the rankings over. Large sites with thousands of addresses, or moves to a new domain, can take several months to settle completely. What matters is the direction: if traffic holds steady or rises after the first weeks, everything is as it should be. If it keeps falling after four to six weeks, there is a concrete problem to find.

What do you do if traffic has already dropped after a new website?

It is rarely too late. Even if the old site has been gone for weeks or months, Google still remembers the old addresses, and links from other sites still point there. The sooner you act, the more you can save. This is how we approach a rescue:

1. Find the old addresses via Search Console, the Wayback Machine, old sitemaps and your analytics tool.
2. Check what each old address returns today: an error, the homepage or the right page.
3. Build the missing redirect map, starting with the pages that brought the most traffic before.
4. Restore content that ranked and was deleted, on the new site.
5. Check for blocks, missing titles and broken internal links.
6. Resubmit the sitemap and track progress weekly in Search Console.

What does an SEO-safe website migration cost?

A worked example: a 15-person company has a site with 120 addresses, 40 of them blog posts, and ten pages account for most of the traffic from Google. Mapping, the redirect map, testing and monitoring in the first month typically take one to two days. At a senior rate of DKK 800–1,400 an hour, that is a small item compared with the website itself, and a very small one compared with losing half the enquiries for a quarter. That is why the migration should be a separate line in the proposal. If it is missing, ask. See also the signs you need a new website if you are still deciding whether it is time.

How does Ceptiv handle website migrations?

When we build a new site for a company with an existing website, the redirect map, carrying over titles and structured data, and monitoring after launch are things we plan for from the start. We build in Next.js with hreflang, sitemap and speed built in, and you can follow progress in our client panel. Read more about our website redesign work, or see what else goes into an SEO-friendly website.

Send the address of your current site and a short description of what should change, and you get a fixed price within 24 hours, with the migration as a clear line in the proposal.