The types of website migration and their scope
Changing host, CMS, domain, content or design: each type of migration has its own risks. The types of website migration, and how to set the scope of yours.
Not all migrations are alike: changing host carries almost no risk for rankings, while changing CMS and site structure at the same time carries a lot. Recognising the type of your migration tells you which risks to prepare for and what scope to give it.
For the definition, steps and cost of a website migration, see our reference article.
The different types of migration
Changing host or server
The files and database move to a new server, without the URLs changing. The risk is low, unless the new server is undersized: slow pages or errors while Google crawls the site degrade indexing.
Changing CMS or platform
Moving from PrestaShop to Shopify, or from Wix or an HTML site to WordPress, almost always changes the URLs, the templates and sometimes the available features. It is one of the riskiest migrations: every old URL needs its redirect. See the procedure for changing CMS and technical migration, which also covers changes of ERP or of an e-commerce site's structure.
Switching to HTTPS
The protocol of every URL changes: each HTTP address must lead, in a single hop, to its HTTPS equivalent. See the HTTPS protocol.
Changing domain name
Often decided for commercial reasons, it involves configuring DNS and the server. It requires a redirect plan sending each URL of the old domain to its equivalent on the new one, so that search engines transfer the rankings earned, and keeping the old domain (see should you renew the old domain name).
Editorial migration
Content and site structure change: shorter URLs (without dates, for example), rewritten pages, content merged so it stops competing with itself. When a page's URL changes, a 301 redirect is needed. An inventory of existing URLs (site crawl, server logs, Google Analytics 4 and Search Console) identifies the pages that bring the most traffic. See editorial migration.
Design migration
It covers appearance and navigation: visual identity, page templates, menus, sometimes new categories for new products or services. It affects internal linking and often the URLs: involve an SEO specialist from the mock-up stage. To avoid duplicates, 301 redirects and canonical tags do the work, and a noindex tag keeps obsolete pages out of the index; the robots.txt file only tells robots which areas not to crawl. See design migration.
Brand migration
After an acquisition or a change of name, it changes the domain name or the brand name, and often comes with a change of CMS or URLs. It stands out for the communication it requires to make the new site known. See migration after an acquisition or a rebrand.
Merging several sites
Bringing several sites together into one concentrates visibility, but every URL of every old site must find its place on the shared site. See migrating several sites by merging them.
Whatever the type of your migration, Swan matches the pages of the old and new site and checks the redirects.
Setting the scope of the migration
A redesign often combines several types of migration. The scope states exactly what changes (URLs, content, templates, domain, platform) and what is migrated. It is set before preparation, because it dictates the work, the budget and the risks to cover.
Taking stock of what exists
Start by finding out what content the current CMS holds (pages, media, metadata, accounts, products) and which items receive traffic or links, using Search Console, Google Analytics 4 and a crawl. Two questions then guide the work: which content is still relevant, and what can or cannot be migrated?
Setting selection rules
Rather than deciding page by page, set rules. For example:
- date: do not migrate pages that have not been updated or visited for two years;
- section: pages of a discontinued activity are not migrated;
- media: only migrate files used in the pages within scope;
- unpublished content: it is not migrated, except seasonal content;
- versions: only migrate the latest published version;
- images: leave out those whose resolution does not suit the new design.
Set the general rules first with a small group (developers, SEO specialist, designer), then let each department refine its own. A page left out that receives links or traffic keeps a redirect to the closest page.
What the scope changes
These rules immediately show the size of the migration, and often reduce it: if three quarters of the pages can go, the effort shifts to the quality of the pages kept. The scope also lets you estimate cost, time and resources (see the price of a migration service), and choose the moment: never during the site's busiest period.
Once the scope is set, move on to the preparation phase of the migration.
