Key takeaways
- Migrations — new domain, CMS, URL structure or redesign — are the riskiest SEO events. Most traffic losses come from missing redirects and lost content.
- Benchmark everything before, build a complete redirect map, test on staging, then monitor closely for 4–8 weeks.
- Change as little as possible at once; separate a domain change from a redesign if you can.
I’ve seen businesses lose 50–80% of organic traffic after a “simple” website redesign, and I’ve seen well-planned migrations that didn’t dip at all. The difference is preparation. Use this checklist for any migration.
Phase 1: plan and benchmark (2–4 weeks before)#
- Define scope: domain change? CMS change? URL changes? Design only?
- Export rankings, Search Console performance (queries and pages) and GA4 landing-page data for the last 12 months.
- Crawl the old site and save every URL, title, meta description, H1, canonical and status.
- Export backlinks by target URL to know which pages carry authority.
- List top pages by traffic, conversions and links — these must be protected.
Phase 2: build the redirect map#
| Old URL | New URL | Notes |
|---|---|---|
| /services/seo.html | /services/seo-audit/ | 1:1 match |
| /blog/2019/05/wp-speed-tips/ | /wordpress-speed-optimization/ | Merged into updated guide |
| /old-promo-page/ | /offers/ | Closest relevant |
- Every old URL with traffic, links or value gets a 301 to the most relevant new URL.
- Avoid chains — point directly to final URLs.
- Don’t mass-redirect to the homepage.
- Include images, PDFs and other files with backlinks.
Phase 3: build and test on staging#
- Keep content of top pages (copy, headings, internal links) at least as strong as before.
- Carry over titles, meta descriptions and structured data.
- Check canonicals, hreflang (if used) and robots meta.
- Test redirects with a crawler using the old URL list.
- Run speed and Core Web Vitals tests on key templates.
- Staging is password-protected and noindexed — see staging guide.
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Phase 4: launch day#
- Remove staging noindex/password and check robots.txt allows crawling.
- Deploy redirects and test a sample immediately.
- Submit new sitemaps; keep the old sitemap briefly so Google recrawls old URLs and sees redirects.
- For domain changes, use Search Console’s Change of Address tool.
- Check analytics and tag tracking are firing.
- Update Google Business Profile, social profiles and important backlinks.
Phase 5: monitor (4–8 weeks)#
- Daily for the first week: 404s, server errors, indexing of key pages.
- Weekly: Search Console clicks and impressions vs benchmark, top-page rankings.
- Crawl the old URL list again to confirm redirects still work.
- Fix issues quickly — the longer problems persist, the bigger the loss.
What’s normal? A small, temporary fluctuation for a few weeks is common, especially with domain changes. Sustained drops usually point to missing redirects, lost content or technical blocks.
Related: WordPress migration, website redesign checklist, 301 redirects.
Site migration FAQ#
How long do redirects need to stay?#
At least a year; ideally permanently for URLs with backlinks.
Should I migrate and redesign at the same time?#
Separating them reduces risk and makes problems easier to diagnose, but it’s not always practical. Plan carefully if combined.
Will changing CMS hurt SEO?#
Not if URLs, content, metadata and site quality are preserved or improved.