The short answer
An SEO migration is the planning and technical work that carries your rankings across when a site changes URLs, platform or domain. It covers the URL inventory, the redirect map, launch checks and post launch monitoring. Done properly, traffic wobbles briefly. Done badly, it doesn't come back.
What the work covers
- A full URL inventory, pulled from more than one source
- A one to one redirect map, reviewed before launch rather than after
- Launch day checks on indexing directives and sitemaps
- Metadata, headings and internal links carried across intact
- Structured data preserved where present
- A verification crawl of every old URL once the new site is live
- Daily monitoring at first, compared page by page
- Fixes done by our own developers. See technical SEO
The migration checklist, in the order it has to happen
Inventory every URL before anything changes
Crawl the live site, then add Search Console pages, analytics landing pages, every XML sitemap and your backlink report. Use all of them, because a crawl only finds linked pages. The unlinked ones are often the old landing page still collecting traffic, or the 2019 post carrying half your links. Do this while the old site exists. Once it's gone you're working from memory.
Map old to new, one to one
Every URL with traffic, links or rankings gets its own destination, matched by what the page was about. The temptation is to point everything at the homepage, because it's one rule and takes minutes. Search engines treat mass redirects to an unrelated page as a soft 404, so the signals those pages carried don't transfer. Where genuinely nothing matches, decide deliberately: the closest category page, or let it go and drop it from the sitemap.
Keep the old structure crawlable during the transition
Don't delete the old site the moment the new one is live. Leave redirects in place permanently rather than for a month. Point every old URL straight at its final destination instead of letting redirects chain through two or three hops, because chains lose signal and slow crawling. Submitting the old sitemap alongside the new one helps search engines find the redirects sooner.
Check that staging isn't indexable, then check the live site isn't
This is the most common self inflicted injury in the job. Either staging gets indexed and competes with the real site, or the new site launches still carrying the noindex tag that was protecting staging. Nothing looks wrong. The site works, the design is fine, and it quietly disappears from search for weeks.
Monitor properly for the first month
Crawl the whole old URL list and confirm each returns one redirect to a live page. Submit the new sitemap, keep the old Search Console property verified, and read the 404 report daily rather than weekly. Compare clicks page by page, not just the site total, because an average hides the fact that your five best pages went missing.
If you're mid rebuild, get the redirect map reviewed before launch. It's the cheapest hour in the project.
Some fluctuation is normal, a collapse isn't
Expect movement. Search engines have to recrawl the new URLs, reassign what they knew about the old ones, and work out which version to rank. Rankings bounce around for two to four weeks and traffic often dips before settling. That is not a failed migration.
What isn't normal: a drop that keeps going past four weeks, 404s climbing in Search Console, your best pages dropping out of the index while the rest hold, or branded impressions falling. Those point at redirects, indexing directives or content that didn't come across. All three are fixable, faster in week one than in month three.
How a migration runs
We inventory and benchmark
Every URL, plus rankings and traffic recorded before launch so there's something honest to compare against.
We build and review the redirect map
Line by line, on the old site's real data, agreed before anyone launches.
We check the launch
Indexing directives, canonicals, sitemaps, analytics and a verification crawl on the day.
We watch it settle
Daily for a fortnight, then weekly, with fixes done rather than reported. Ongoing through SEO.
Who this suits, and who it doesn't
It suits anyone replatforming, changing domain, merging two sites, or launching a rebuild through website design where the URLs change.
It's a poor fit if the site has no rankings or links worth protecting. Then it's just a launch, and migration work would be insurance on an empty house.
Why this is worth doing with someone
The fixes get done, not listed.
Our developers make the changes. You don't receive a document explaining what your developer should have done.
Search and build sit in the same office.
The people writing the redirect map can talk to the people building the new site, before the URLs are set.
No lock in contracts.
Month to month, and you keep every document we produce.
"We already migrated and traffic dropped."
We take these on regularly. It's the same checklist run backwards: rebuild the old URL list, find what's redirecting to nowhere, fix the directives. Recovery is realistic, and slower than doing it right first time.