Migrating a website without losing SEO: step by step

You migrate a website without losing SEO in three moves: send every old URL with a permanent 301 redirect to the best-matching new page, test everything first on a protected staging environment, and follow up weekly for a few weeks after launch. According to Google, keep those redirects in place for at least a year ^[1].

Getting a website built with AI? Ask your builder before you sign how they handle this. Below is Google's step-by-step plan, supplemented with what a Belgian site needs on top: several languages and hosting that also lets AI crawlers in.

Step 1: make an inventory of your old URLs

Before a single page is built, you need to know which old URLs have value. Collect:

• All URLs, with a crawler: including PDFs, images and forgotten pages.
• The pages with traffic from Google, from Search Console. The performance report keeps 16 months ^[2]; take that whole period, so seasonal pages don't drop out of sight.
• The pages that bring in enquiries, per landing page in Google Analytics 4.
• The pages with external links, from the links report in Search Console.

Then decide per URL: keep, improve, merge or remove. Only a page without traffic, links or a related replacement may return a 404 or 410.

Plan the timing too. Google recommends changing one thing at a time, moving a small or medium-sized site in one go and choosing a quiet period ^[1]. If you change content and URL structure at the same time, Google says you will probably lose some traffic ^[3].

Don't know which pages of your current site bring in traffic, or which ones Google does not index? The free website scan maps it out.

Step 2: redirect every old URL with a 301

Make a redirect map with two columns: old URL, new URL. A spreadsheet will do; then you set up the redirects as permanent redirects on the server ^[1]. The rules:

• Permanent: 301 or 308. For Google that is a strong signal that the page has moved; a 302 or 307 is temporary and only a weak signal ^[4]. According to Google, permanent redirects don't cost PageRank ^[1].
• Not everything to the homepage. Sending many old URLs to one unrelated page can be treated as a soft 404 ^[1]. Merging pages on the same topic is fine.
• No chains. Point directly to the final destination; Google recommends preferably no more than three steps ^[1].
• Internal links and canonicals point to the new URLs straight away ^[1].
• Keep them for at least a year, and for your visitors preferably forever ^[1].

Two or three languages? Redirect every French page to its French successor, not to the Dutch version or the homepage. Update the hreflang annotations to the new URLs ^[1]. Each language version refers to itself and to the others; without that reciprocity, Google ignores the tags ^[5].

Step 3: test on a protected staging environment

Set the staging environment to noindex ^[6] or put it behind a password ^[7]; a robots.txt alone does not keep pages out of Google ^[7]. Keep a list of every noindex that has to go at launch ^[1]. Then check with a crawler that every old URL lands on the right page with a single 301, and that internal links, titles, canonicals and hreflang are correct.

New hosting? Let the crawlers in. Google asks you to check that your firewall does not block Googlebot ^[6]. The same goes for AI: if you block OAI-SearchBot, you won't appear in ChatGPT's search answers ^[8].

If your site sits behind Cloudflare, check what is switched on there. Cloudflare announced that from 15 September 2026 it will block bots for training and agents by default for new domains on pages with ads ^[9], and its managed robots.txt adds Disallow rules for AI crawlers ^[10]. Which bots you had best allow is covered in how to get found in ChatGPT.

Step 4: work through launch day

1. Redirects live. Test a sample of old URLs: do you get a 301 to the right page?
2. Blocks removed: every noindex and every robots.txt rule that was only there for staging ^[1].
3. Submit sitemaps in Search Console and Bing Webmaster Tools.
4. Different domain? After the redirects, file a Change of Address for every variant of the old domain, including www ^[1], ^[3]. Keep the old domain for at least another year ^[3].
5. Test tracking and forms. A thank-you page with a new URL can break your measurement. Cédric explains how to measure enquiries correctly in GA4 key events and conversions.
6. Update the links you control: Business Profile, social profiles, email signature and ads.

Step 5: follow up during the first weeks

For a small to medium-sized site, it takes a few weeks before most pages have moved ^[1]. Google may show old URLs for a while ^[11], and after a hosting change Googlebot may temporarily visit less often ^[6]. So panicking after three days is premature.

Check weekly in Search Console which old URLs return a 404, whether your new pages are getting indexed and how traffic per landing page is developing. If a drop persists after a few weeks, look for a missing redirect, lost content, a forgotten noindex or a firewall. Put the 404s next to your redirect map; that is usually where you find the cause.

Why you might want to leave WordPress, or not, is covered in WordPress or a static website. To plan a new site from quote to the first 90 days, use the checklist for a new SME website.