Migrating a website is a delicate and strategic operation. Poorly planned, an SEO migration can lead to a drop in traffic and visibility. But if well executed, it is entirely possible to preserve, or even improve, your organic rankings.

In this article, we review the essential steps to ensure a successful SEO migration and maintain your visibility in search results.

What is an SEO migration?

SEO migration goes hand in hand with website migration. A website migration involves moving an existing website to a new domain name or platform: that’s the technical side. When we talk about an SEO migration, we mean performing this transfer while optimising search engine visibility and avoiding any loss of rankings.

There are several situations where you might need to carry out an SEO migration:

When switching from HTTP to HTTPS (a more secure protocol enabled by an SSL certificate)
When changing your CMS platform (such as WordPress, Drupal, Squarespace…)
When performing a redesign that involves a new site structure,
When changing your domain name or extension

💡 A good domain name strengthens your brand image: discover our 15 tips for choosing the right domain name.

📝 With over 1,300 extensions available at Netim, our dedicated guide will help you choose the ideal extension for your business sector.

Preparing your SEO migration

A successful migration largely depends on the preparation done beforehand. Here are the key steps to prepare for your migration.

Analyse your current website

The first step is to perform a full audit of your website. You can use Google Search Console or a crawler (a tool that scans your site) such as Screaming Frog, OnCrawl, or Sitebulb to extract:

a complete mapping of all your site URLs,
titles, meta descriptions and h1 tags (HTML tags that indicate a page’s title),
internal and external links (links pointing to or from your site),
your most visited and best-ranked pages.

💡 Keep this data: it will serve as a basis for your redirection plan and post-migration checks.

Back up your website

Before making any changes, create a full backup of your site, including files, database, configurations and content. This will allow you to restore it if anything goes wrong.

Create a secure testing environment

Before making changes, you should work on a test version of your site: a staging site or pre-production site. This is a copy of your website that isn’t yet live, where you can make modifications and test new features before deployment. This version must remain private: search engines and visitors should not be able to access it.

💡 To do this, you can use password or IP restriction and/or add the tag within the section of your site’s HTML pages.

Rethink your site structure

If your goal is to restructure, refresh or redesign your website, it’s important to rethink its structure. Search engines favour clear, logically organised architectures. The aim is to create an optimised site structure and SEO-friendly content.

To start, review your products and services: are they all properly showcased on your site? Take the opportunity to clean things up! Are there any redundant or outdated pages? Any that compete with one another?

💡 Use tools such as Semrush or Ahrefs to understand your visitors’ search intent (what questions they ask) and identify new keyword opportunities.

Optimise your content

Once your structure is defined and optimised, you can move on to the editorial update of your content: rewriting or creating pages based on your new categories, integrating identified keywords, and ensuring each page has a clear purpose for both visitors and search engines.

💡 Focus on readability and value for your audience: quality content remains the most powerful SEO lever. To achieve this, make sure you have:

unique content that stands out from competitors,
structured titles and subtitles (h1, h2, h3 tags, etc.),
short, relevant meta descriptions to feed the SERP,
pages enriched with optimised media (lightweight images for performance, descriptive alt attributes for accessibility, videos, etc.),
a solid internal linking strategy to connect your pages and strengthen your SEO structure,
…and read our article on How to optimise a blog post? for more SEO writing tips.

Ideal hierarchy of Hn tags on a page

Check technical SEO aspects

Once the content is updated, make sure that all technical SEO recommendations have been applied throughout your website. Here are some key best practices:

Mobile first! Ensure your site is responsive, that is, it displays correctly on all devices. Google’s crawlers and most visitors browse primarily on mobile.
Canonical tags are essential to avoid duplicate content. They indicate which page should be considered the main one. Place them in the <head> section of your HTML page: <link rel="canonical" href="https://www.netim.com/en" />
If your website is available in multiple languages, don’t forget to include hreflang tags on every page. These tell search engines which version of the page to serve depending on the user’s language or location. Example:
- <link rel="alternate" href="https://www.netim.com/fr" hreflang="fr" />: French version
- <link rel="alternate" href="https://www.netim.com/en" hreflang="en" />: English version
- <link rel="alternate" href="https://www.netim.com/en" hreflang="x-default" />: default version for users whose language isn’t defined.
Site speed and performance are crucial for both users and SEO. Check your page speed using tools such as Google Search Console, Lighthouse, or GTmetrix, and follow their recommendations: compress media, minify CSS and JavaScript files, enable caching, etc.
Add structured data to your pages. These are code elements, often in JSON format, embedded in your pages to provide search engines with detailed information about your content. They enable rich results (“rich snippets”) to appear in search results: for example, star ratings, product prices, recipes, events, etc. Learn more and find examples on Schema.org. You can also test your code using Google’s tool: Rich Results Test.

Crawl your website

Your pre-production site is now ready: structure, design, content, SEO. It’s time for a pre-migration crawl (with tools such as Botify, OnCrawl, or Screaming Frog). This crawl gives you a full list of your new URLs and helps identify any errors (404 pages, redirect chains, duplicate content).

Once errors are fixed, you now have both old and new URLs, and you’re ready for the final step: the redirection plan.

Build your redirection plan

First, establish the mapping between your old and new URLs using the exported crawl files from both versions of your site.

Then, set up permanent redirects (301 redirects) to inform search engines that a page’s address has changed permanently. This ensures that the “SEO juice” (authority, backlinks, rankings) is transferred from the old page to the new one, and users are redirected instead of hitting a 404 error.

The redirect configuration method depends on your server or CMS. For example, in a CMS (like Drupal, Joomla, PrestaShop, Shopify…), redirects can be configured through a simple interface where you specify the old and new URLs. Otherwise, they can be set in your server configuration file. For example, redirecting the old homepage to the new one:

On Apache, in the .htaccess file: RewriteRule ^netim.fr$ https://www.netim.com/en/ [R=301,L]
On Nginx, in the /yoursite.conf file: rewrite ^/netim.fr$ https://www.netim.com/en/ permanent;

Once redirects are set up, run tests and a final verification crawl to ensure all pages and redirects work properly on the staging site. You can now generate a new sitemap.xml file and submit it to Google after migration.

💡 Don’t forget to document your tracking tags and UTM links in your analytics tools (Google Analytics, Google Tag Manager, Matomo, AT Internet…) to maintain data continuity before and after migration.

Schedule the migration

It’s important to carefully plan migration day in advance:

Choose a date when all key people are available,
Prefer the start of the week in case major fixes are needed (avoid Fridays!),
Carry out the migration at a time when your site’s traffic is low (very early in the morning, for example) to minimise disruption,
Prepare a checklist of all necessary actions to avoid oversights on the day.

Attention:

If you are changing your hosting or CMS, make sure to update the TTL (Time To Live) in your domain’s zone file to help speed up DNS propagation on migration day. This defines how long a DNS resolver waits before checking for updated zone data.

Doing so will avoid long waiting times (usually 24 to 48 hours depending on the registrar) before your domain points to its new hosting and/or CMS.

24 to 48 hours before migration: Set the TTL between 300-600 seconds (5-10 minutes)
After migration: Restore the TTL to its normal value, typically 3600s (1h) or more.

Carry out your SEO migration

The big day has arrived: grab your checklist and get ready for migration! 💪

Activate maintenance mode

First things first, make sure to put your website into maintenance mode (code 503) with a custom message to inform both users and search engine crawlers about the temporary unavailability of your site.

To do this, create a maintenance page that returns the HTTP status code 503 “Service Unavailable”. For example, if your site uses PHP, add these lines at the very top of your main PHP file, in the header:

<?php header('HTTP/1.1 503 Service Temporarily Unavailable'); header('Status: 503 Service Temporarily Unavailable'); ?>

Then, redirect all your traffic to this page using a “RewriteRule” on Apache or Nginx. If you’re using a CMS, simply enable the built-in maintenance mode, which will handle everything automatically.

Deploy and test your new pages

It’s time for the go-live: implement your planned redirects and set up the 301 redirects on your old domain.

Now comes the moment of truth. Launch a new crawl using your preferred tool to identify potential errors and begin post-migration testing: check thoroughly that all redirects work properly, that your robots.txt file at the root of your site is correct, and that nothing has been missed.

Stay alert and focused: if an error occurs, act quickly to fix it and avoid putting an incomplete or faulty site online.

Once all checks are completed and issues resolved, you can:

Deactivate maintenance mode,
Lift access restrictions (password or IP),
Allow your pages to be indexed again,
Check your tags and UTM links are properly configured in your analytics tools,
Submit your new sitemap.xml to Google via the Search Console

Your SEO migration is complete! 🎉

Monitor and control your SEO migration

The migration is done, but the most important part is now making sure everything continues to run smoothly. This consolidation phase can take several weeks: patience and regular monitoring are your best allies.

Check the indexation of your new site

Within the Google Search Console, ensure that the old domain is gradually being de-indexed, while the new one’s indexation is increasing.

Example of the progressive de-indexation of old pages

Example of pages from a new site waiting for indexation: if the number increases, that’s a good sign!

💡 Keep your old domain active for at least 6 to 12 months so Google can follow the redirects and transfer the SEO “juice”.

Analyse performance

In your analytics tools (Google Analytics, Matomo, AT Internet…), track traffic, impressions, click-through rates and your rankings in the SERP.

As with indexation, the graphs should show a downward trend for the old site and an upward trend for the new one. Compare your old data with the new results. Are your positions stable? If you’ve lost some, are they recovering?

Develop your backlinking

A backlink is a link from an external site pointing to yours. Backlinks help improve Google’s trust in your site and therefore your organic ranking.

If you haven’t already, take the time to notify your clients, partners, and suppliers about your website’s new URL and ask them to update the most important backlinks.

Even if your redirects are in place, they add extra loading time and can dilute the SEO “juice”. Updated links allow for faster responses, transmit more value, and ensure the long-term stability of your link profile (the backlink will still exist even if the redirect is later removed).