Site migration
SEO migrations: protecting visibility when a site is rebuilt
Most traffic lost in a redesign is lost to a missing URL map, not a new design. What to benchmark before launch, how to map redirects, and what to watch afterwards.
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A rebuild is the moment a site is most exposed. Every URL, title, heading and internal link can change at once, and search engines have to re-derive what the site is from scratch. Handled carelessly, years of accumulated visibility is discarded in an afternoon.
Key takeaways
- Benchmark index coverage, top pages and rankings before anything changes — you cannot measure recovery without a baseline.
- Map every indexed old URL to one new URL; redirect to the closest equivalent page, never blanket-redirect to the home page.
- Carry titles, headings, canonicals and structured data across, or the new page is a different page to a crawler.
- Expect fluctuation for weeks after launch; judge recovery against the benchmark, not against the day before.
Short answer
An SEO migration is the work of preserving what search engines already understand about a site through a structural change: a complete URL map, one-to-one 301 redirects, content parity, and monitored recovery.
Before: benchmark and inventory
Two artefacts have to exist before anything is deployed. Without them there is no way to tell whether the migration succeeded.
- A benchmark: index coverage, top landing pages, current rankings and organic traffic by page.
- An inventory: every indexed URL, not just the ones in the navigation.
- A map: each old URL against exactly one new URL, reviewed line by line.
- A parity check: titles, headings, canonicals and structured data carried across.
Old URLs mapped to new structure
Diagram mapping old URLs to a new information architecture, including merged topics and removed pages
Old URL inventory
Every indexed address, not just the nav
New information architecture
Where each topic now lives
Direct match
301 to the equivalent page
Merged topic
301 to the page that now covers it
No equivalent
410 or a considered parent redirect
WhyClose
Redirecting everything without a match to the home page tells search engines the old page is gone and the new one is irrelevant. A parent page in the same topic is better; an honest 410 is better still.
No redirect chains, no loops
Each old address resolves in one hop
The rules that prevent most losses
| Situation | Handling |
|---|---|
| Page moved to a new address | 301 to the new address |
| Two pages merged into one | 301 both to the surviving page |
| Content genuinely removed | 410, or 301 to the parent section |
| Address unchanged | Leave it alone; do not redirect for tidiness |
| Redirect points to another redirect | Collapse to a single hop |
Content parity matters as much as the redirect. A crawler comparing a 900-word page against its 200-word replacement does not see the same page at a new address; it sees a different, thinner page.
Launch and after
Before, launch, after
- Day one: redirects verified in bulk, XML sitemap submitted, robots.txt checked, analytics confirmed.
- First weeks: crawl errors, index coverage, redirect chains, 404 logs.
- First months: rankings and organic traffic compared against the benchmark, page by page.
When JMGGroup.ca moved off WordPress, the old addresses were mapped one-to-one before the new build shipped, which is why the rebuild reads as an architecture change rather than a reset.
Practical test
Ask for the URL map before the launch date. If nobody can produce one, the launch date is not real.
Migrations are the clearest case for treating search as structure. Planning them is part of SEO and content architecture.
Frequently asked questions
- Why do websites lose traffic after a redesign?
Almost always because URLs changed without a complete redirect map, or because content that carried the rankings was shortened or removed in the redesign. The visual design is rarely the cause.
- What kind of redirect should be used?
A 301 permanent redirect for anything that has moved. Temporary redirects tell search engines the old address will return, which is not what a migration means.
- Should old pages redirect to the home page?
No. A blanket redirect to the home page tells search engines the old content is gone and nothing replaced it. Redirect to the closest equivalent page, or to the parent section, and return 410 for content that genuinely no longer exists.
- How long does recovery take after a migration?
Fluctuation for several weeks is normal while pages are re-crawled and re-assessed. What matters is the trend against the pre-launch benchmark rather than the first few days.
- Can a rebuild improve search visibility?
Yes, when the new structure is better designed for search rather than merely newer. That was the case in our own rebuild, where the content model replaced hand-maintained pages.
Next step
Planning a site rebuild?
Map the migration, redirects and search risks before launch.
Or run a Business Growth Audit of your website firstNeed help with this?
Planning a rebuild or migration?
Protect rankings, redirects and technical SEO before launch.