SEO migrations
Change your site, domain or CMS without losing what you've earned on Google
We plan and support domain, platform, redesign, HTTP-to-HTTPS and URL structure migrations. A complete inventory, a 301 redirect map, testing on a staging environment, a launch day run from a checklist and weeks of monitoring afterwards.
The risk
A migration is when you can lose the most traffic in one go
Every URL that ranks today has accumulated signals: external links, history in Google's index, relevance for specific searches. When you change that URL's address, template or content, you are asking Google to evaluate it again. If the new version is equivalent and the redirect is correct, the signals carry over. If not, they are lost.
Most traffic drops after a launch are not caused by ‘something changing at Google’ but by avoidable mistakes: missing redirects, a forgotten noindex, trimmed content or internal links still pointing to the old version. That is why we treat a migration as a project with phases, owners and acceptance criteria, not a last-minute task.
If you want to understand the process in detail before talking to us, read our guide Migrating a website without losing SEO.
Common causes
Why traffic gets lost in a migration
URLs not redirected, or redirected to the home page
Old pages return 404s or are redirected en masse to the home page. Google treats mass redirects to the home page as soft errors and the signals do not carry over.
The staging noindex or robots.txt reaches production
The test environment was blocked, as it should be, and the block goes live with the new site. It is one of the most frequent mistakes and one of the easiest to prevent with a checklist.
Ranking content gets cut or merged
The new design ‘tidies up’ copy, removes pages with traffic or merges distinct topics. The page still exists but no longer answers the searches that made it visible.
Redirect chains and wrong canonicals
Redirects that chain three or four hops, canonicals pointing to the old domain or to staging, broken hreflang between language versions.
Internal links pointing to old URLs
Menus, content and sitemaps keep linking to the old addresses. They work thanks to the redirect, but they dilute signals and slow down crawling.
Content that only appears with JavaScript
The new front end loads text and links in the browser. Google may render it with a delay, and many AI crawlers do not render it at all.
Process
The phases of a well-run migration
Inventory and baseline
Before changing anything, we record the current state: every indexable URL, those receiving organic traffic, those with external links, their titles, content and structured data. We combine a full crawl with data from Search Console, Analytics, sitemaps and link tools.
We also take a performance snapshot (clicks, impressions, rankings for key queries, conversions) so we can compare rigorously after launch.
Activities
Outputs
- Prioritised URL inventory
- Performance baseline
Redirect map
Every old URL with value is mapped to its closest equivalent on the new site with a one-to-one 301 redirect. Pages with no equivalent are assessed case by case: redirect to the most relevant category, or return a 410 if the content genuinely no longer makes sense. Never mass redirects to the home page.
We check that the map creates no chains or loops, and that it covers variants with and without trailing slashes, upper-case letters, parameters and old HTTP or www versions.
Activities
Outputs
- Validated redirect map
- Rules ready for the server or CMS
Staging and testing
The new site is reviewed on a password-protected staging environment with noindex, so it cannot be indexed by accident. There we crawl the new version and check titles, canonicals, hreflang, structured data, internal links, performance and rendering, and test the redirect map against the list of old URLs.
The phase ends with a report of blocking and non-blocking issues and a clear rule: no launch with open blockers.
Activities
Outputs
- Issue report
- Launch sign-off
Launch day
We pick a low-activity window and are on hand during deployment. We remove the noindex and staging protection, switch on the redirects, update robots.txt and sitemaps, and check a broad sample of old and new URLs live.
For a domain change we verify the new property in Search Console and use the Change of Address tool. We submit the new sitemaps and, temporarily, one listing the old URLs too, to help Google discover the redirects sooner.
Activities
Outputs
- Completed launch checklist
- Launch-day issue log
Post-launch monitoring
Over the following weeks we monitor coverage and indexing, 404 errors, crawling, rankings for key queries, traffic and conversions against the baseline. Some early fluctuation is normal; an entire section disappearing is not, and that gets spotted in days, not months.
Redirects should stay in place for at least a year, and ideally should never be removed while they still receive visits or links.
Activities
Outputs
- Weekly monitoring reports
- Migration close-out report
Checklist
Essential checks by phase
A summary of what we verify in every migration. The full list is adapted to the type of change and your platform.
| Phase | Check | Why it matters |
|---|---|---|
| Before | Inventory of URLs with traffic, links and conversions | Without an inventory you don't know what to protect or redirect. |
| Before | Baseline of clicks, rankings and conversions | Lets you tell normal fluctuation from a real problem. |
| Staging | Password protection and noindex | Stops Google indexing a duplicate copy of your site. |
| Staging | 301 map tested against every old URL | Catches gaps, chains and loops before they affect users. |
| Staging | Equivalent titles, content, canonicals, hreflang and Schema | The new page must be able to take the old one's place. |
| Launch | Noindex and robots.txt blocks removed | The most common and most damaging launch-day mistake. |
| Launch | New sitemaps and Change of Address in Search Console | Speeds up discovery of the new structure. |
| Launch | Analytics and conversion tags working | Without measurement there is no way to evaluate the migration. |
| After | Monitoring of 404s, indexing and performance by section | Lets you fix in days what would otherwise take months to notice. |
| After | Internal links and external profiles updated | Reduces reliance on redirects and strengthens the new URLs. |
Has your migration already gone wrong?
We also step in after a launch that has lost traffic: we compare the previous state with the current one, rebuild the missing redirect map and prioritise recovery of the pages that carried the most value. The sooner you act, the better.
FAQ
About migrations
How far ahead of launch should I get in touch?
As early as possible, ideally while the new architecture is being defined and before the design is signed off. That way SEO can shape decisions that are expensive to change later, and there is time for the inventory, the redirect map and staging tests.
Is it normal to lose some traffic after a migration?
Some fluctuation in the first few weeks is common while Google processes the changes. A well-executed migration should settle; we cannot promise there will be no variation at all, but we can minimise avoidable risks and spot any problem quickly.
What is the difference between a 301 and a 302 redirect?
A 301 signals a permanent move and is the one used in migrations. A 302 signals a temporary one; Google may end up treating it as permanent if it stays in place, but it is better not to leave that to interpretation.
Can you work with our development team or another agency?
Yes, that is the most common set-up. We provide the inventory, the redirect map, the SEO requirements and the testing; your team implements. We coordinate through whatever tools you already use.
Is moving from HTTP to HTTPS a migration too?
Yes, technically every URL changes. It needs a 301 redirect from each HTTP URL to its HTTPS version, updated canonicals, internal links and sitemaps, and a check for mixed content. These days it is usually done alongside other changes.
What if I merge two websites into one?
That is one of the most delicate migrations, because you have to decide which content survives and how two histories are combined. We inventory both sites, resolve topical overlaps and design a joint redirect map.
Related
To prepare your migration
Migrating a website without losing SEO
How to migrate a website without losing SEO: URL inventory, 301 redirect map, protected staging, launch-day checklist and post-launch monitoring, step by step.
SEO checklist
Interactive SEO checklist with 80+ points: technical, indexing, on-page, content, E-E-A-T, local, international, AI search readiness, analytics and links.
Technical SEO
Technical SEO: crawling, rendering, indexing, Core Web Vitals, site architecture, canonicals, hreflang, structured data, log file analysis and JavaScript SEO.
Is a migration on the horizon?
Let's review your current site before anything changes. Start with an audit and a tailored migration plan.