A site migration can be good for your business, but only if SEO is treated as part of the project from the start. A new website, cleaner design, better CMS, faster templates or stronger UX can all help growth. But if search engines lose track of your pages during the move, you can quickly lose rankings, traffic and enquiries.
That is why a site migration SEO audit matters. It gives you a clear process before launch, during launch and after go-live, so you are not relying on luck when the new site is pushed live.
In the UK, this is not a small risk. ONS data shows that internet retail sales in Great Britain reached £2.662 billion in May 2026. Even if you are not an ecommerce business, your website still has a commercial job to do. If organic traffic drops after a migration, the cost is not just “a few lost clicks”. It can mean fewer enquiries, fewer quote requests, fewer applications and weaker pipeline.
The practical answer is simple. Plan properly. Map your URLs. Test your redirects. Check the site again after launch. Then keep watching the data until performance settles.
If you need support with the technical side, a proper technical SEO agency London can help you avoid the expensive mistakes that often appear after a rushed migration.
What counts as a site migration?
A site migration is any major change that affects how users and search engines access your website. It is not only a full domain move.
You may be migrating if you are:
- Moving from one CMS to another
- Changing your URL structure
- Redesigning your website
- Moving from HTTP to HTTPS
- Combining 2 or more websites
- Moving to a new domain
- Relaunching major templates
- Replatforming an ecommerce site
- Changing navigation or site architecture
- Moving content into new folders or subfolders
Some migrations are small. Others touch thousands of URLs. Either way, Google has to understand what changed, where old content moved, and which new pages should be indexed.
This is where a structured SEO audit agency approach is useful. You are not just checking for broken pages. You are checking whether the new website protects the value your current website has already built.
Why migrations go wrong
Most migration issues come from moving too fast and checking too late.
A redesign may look finished from a brand or design point of view, but SEO can still be exposed. Old URLs may not redirect. Important pages may be missing. Internal links may still point to staging URLs. Metadata may be duplicated. Canonicals may point to the wrong version. Tracking may be broken. A robots.txt rule used during development may accidentally block the live site.
These are not rare problems. They are common.
The risk is higher when SEO is added at the end of the project instead of being built into planning, design and development. By then, it is harder and more expensive to fix structural issues.
A good migration process should involve SEO, content, development, UX, analytics and commercial teams. The goal is not to slow the project down. The goal is to avoid launching something that looks better but performs worse.
If your migration is part of a wider rebuild, it is worth connecting SEO with website design and development from the beginning rather than treating it as a final QA task.
Start with a pre-launch SEO audit
The pre-launch audit is where you build your safety net.
Before anything goes live, you need to understand the current site. Which pages get traffic? Which pages rank? Which URLs have backlinks? Which pages drive leads or sales? Which pages are important because they support user journeys, even if they do not get huge traffic?
Do not just crawl the website and call it done. A crawl is useful, but it does not tell the whole story. You should combine data from:
- Google Analytics
- Google Search Console
- Current XML sitemaps
- Backlink tools
- Server logs where available
- PPC landing page reports
- CRM or lead tracking data
- Current website crawl data
- Internal business knowledge
This gives you a full picture of what must be protected.
A page with only 200 visits a month may still matter if those visits convert into £20,000 of pipeline. A blog post may not convert directly, but it might attract links that support the wider domain. A service page may not have the highest traffic, but it may rank for a priority commercial keyword.
This is where an organic marketing view helps. You are not only protecting URLs. You are protecting the role each page plays in the wider search and conversion journey.
Create a migration benchmark before launch
You need a benchmark so you can spot problems after launch.
Before migration, record your current performance. This should include:
- Organic sessions
- Organic enquiries or sales
- Top landing pages
- Top ranking keywords
- Indexed pages
- Crawl errors
- Core Web Vitals
- Backlinked pages
- Conversion rate by landing page
- Revenue or lead value where available
For ecommerce, also record product and category performance. For lead generation websites, record form submissions, phone clicks, booked calls, downloads and other key events.
As a simple example, imagine your organic traffic brings 8,000 visits per month, converts at 3%, and each qualified enquiry is worth around £500 in potential revenue. A 25% migration drop could mean around 60 fewer enquiries in a month. That is not an SEO reporting issue. That is a commercial issue.
This is why a good Google Analytics agency London setup matters before the migration happens. If tracking is wrong before launch, you will struggle to understand what changed afterwards.
Build a proper redirect map
Redirect mapping is one of the most important parts of a migration.
Your redirect map tells browsers and search engines where each old URL has moved. If a page has a new URL, the old URL should usually point to the most relevant new URL using a 301 redirect.
A strong redirect map should include:
- Old URL
- New URL
- Page type
- Status code
- Priority
- Traffic level
- Backlink value
- Notes for developers
- QA status
Do not redirect everything to the homepage. That may feel easy, but it is poor for users and weak for SEO. If someone lands on an old product, service or guide URL, they should be taken to the closest equivalent page.
If there is no equivalent page, choose the most useful alternative. If there is genuinely no relevant replacement, a 404 or 410 may be cleaner than sending users to an unrelated page.
Redirects should also avoid chains. A redirect chain happens when URL A redirects to URL B, and URL B redirects to URL C. This slows things down and makes crawling less efficient. The old URL should point directly to the final destination.
If you are already thinking about redirect rules, read Totally.Digital’s guide to redirect strategy for redesigns for a deeper look at how to avoid ranking loss during a site rebuild.
Protect your highest-value URLs first
Not every URL has the same value. Your first priority should be the pages that contribute most to visibility, authority and revenue.
Focus on:
- Pages with strong organic traffic
- Pages with high-quality backlinks
- Pages ranking for commercial keywords
- Pages used in paid campaigns
- Pages that convert well
- Pages linked from key navigation
- Pages included in important user journeys
- Pages with strong internal link equity
This is especially important for B2B websites, where the buying journey is often longer. A guide or insight page may support a future lead even if it does not create an enquiry immediately.
If you are working in a complex buying cycle, a B2B SEO strategy can help you decide which pages matter most commercially, not just which pages get the most traffic.
Check your staging site before launch
Your staging site should be reviewed properly before launch. This is your chance to catch issues before users and search engines find them.
Check the staging site for:
- Missing pages
- Wrong templates
- Broken internal links
- Missing metadata
- Duplicated titles
- Missing H1 headings
- Incorrect canonicals
- Incorrect noindex tags
- Blocked resources
- Slow page templates
- Missing schema
- Broken forms
- Incorrect tracking
- Staging URLs in links
- Image issues
- Mobile usability problems
Pay close attention to robots.txt and noindex settings. During development, it is normal to block staging from search engines. But those settings must not be carried across to the live website.
You should also compare the old and new crawl. If your old site had 1,200 indexable URLs and the new crawl shows 600, you need to know why. Some removals may be deliberate. Others may be mistakes.
This is where SEO web design is useful. The best-looking site still needs crawlable pages, clean templates and a structure search engines can understand.
Review content before you migrate it
A migration is a good time to clean up content, but you need to be careful.
Do not delete pages just because they feel old. Check whether they rank, attract links, support internal linking or help users understand your services. If content is thin, outdated or duplicated, decide whether to update it, merge it or redirect it.
A content inventory should include:
- Keep
- Improve
- Merge
- Redirect
- Remove
For each key page, check the title tag, meta description, H1, subheadings, body content, internal links and calls to action. Make sure the new version still targets the right intent.
If you are changing content heavily during the migration, benchmark performance carefully. If rankings move after launch, you need to know whether the cause was the technical migration, the content change or both.
A good insight and strategy phase can help you avoid making content decisions based only on opinion.
Do not forget internal links
Redirects are important, but they should not be used as a substitute for clean internal links.
After migration, internal links should point directly to the new URLs. This includes:
- Main navigation
- Footer links
- Breadcrumbs
- Blog links
- Service page links
- Related content modules
- Product or category links
- XML sitemap links
- HTML sitemap links
- CTA buttons
Internal links help users and crawlers understand your site structure. If all your internal links still point to old URLs, you are creating unnecessary redirects across your own website.
This can slow crawling, weaken user experience and make the migration messier than it needs to be.
It is also a good time to review anchor text. Use descriptive, natural anchors. Do not force keywords everywhere, but do make sure links explain where they go.
Make analytics and tracking part of QA
Migration QA is not only about SEO tags and redirects. Tracking matters too.
You need to know whether users are still finding the right pages, completing forms, clicking calls to action and moving through the website as expected.
Before launch, check:
- GA4 configuration
- Google Tag Manager setup
- Conversion events
- Form tracking
- Phone click tracking
- Ecommerce tracking
- Consent mode
- CRM integrations
- Paid media pixels
- Dashboard filters
- Cross-domain tracking where relevant
If a migration breaks tracking, your data may look worse or better than reality. Neither is helpful.
For cleaner measurement, review your Google Tag Manager setup before launch and make sure event tracking works on the new templates. You should also connect this with wider data and analytics reporting, so stakeholders can see what changed after go-live.
Launch day SEO checklist
Launch day should not be chaotic. You should have a clear checklist and named owners for each task.
Here is a practical launch day structure:
| Area | What to check | Why it matters |
|---|---|---|
| Redirects | Test old URLs against the redirect map | Protects rankings, users and link equity |
| Indexation | Check robots.txt, noindex tags and canonicals | Prevents accidental blocking |
| Tracking | Test GA4, GTM and conversions | Keeps reporting reliable |
| Forms | Submit test enquiries | Protects lead generation |
| Navigation | Check menus, footers and breadcrumbs | Supports users and crawlers |
| XML sitemap | Submit the new sitemap in Search Console | Helps search engines discover new URLs |
| Speed | Test key templates | Protects UX and conversion rates |
| Mobile | Check priority pages on mobile devices | Reflects real user behaviour |
| Paid media | Check all paid landing page URLs | Prevents wasted ad spend |
| Search Console | Monitor coverage and crawl issues | Helps spot problems early |
Do not rely on 5 manual checks and hope everything is fine. Test a sample of priority URLs, templates and edge cases.
For large sites, bulk testing is essential. You need to know whether redirects work at scale, not just on the homepage and 3 service pages.
Post-go-live QA: the first 24 hours
The first 24 hours are about catching obvious problems quickly.
Check whether the site is live, accessible and indexable. Crawl the live site. Test redirects. Submit the new sitemap. Inspect priority URLs in Google Search Console. Check that GA4 is collecting data. Test forms, calls to action and checkout flows if relevant.
You should also compare the live crawl against the staging crawl. Any unexpected differences need to be reviewed.
In the first day, focus on:
- 404 errors
- 500 server errors
- Redirect failures
- Incorrect canonicals
- Accidental noindex tags
- Broken navigation
- Missing metadata
- Missing tracking
- Form failures
- Slow key pages
This is not the time for panic over small ranking movements. Some fluctuation is normal. The priority is to make sure search engines and users can access the right pages.
Post-go-live QA: the first 2 to 4 weeks
The first few weeks are where deeper migration issues usually appear.
You should monitor:
- Organic clicks
- Organic impressions
- Ranking changes
- Indexed URLs
- Crawl errors
- Redirect hits
- Landing page performance
- Conversion changes
- Core Web Vitals
- Backlinked URLs
- Sitemap coverage
- Server logs if available
Compare performance against your pre-launch benchmark. If traffic drops, check whether the decline is sitewide or limited to certain sections. A sitewide drop may suggest technical issues. A section-specific drop may point to redirect, content, template or internal linking problems.
Do not look only at traffic. Look at enquiries, sales, revenue and lead quality too. A small traffic drop may be acceptable if low-value pages were removed and conversions are stable. A small traffic increase may still be a problem if key commercial pages have lost visibility.
For a wider view of how poor planning can affect visibility, Totally.Digital’s article on SEO migration failures is a useful reminder of why this work matters.
Common migration mistakes to avoid
Most migration mistakes are avoidable if the right checks happen at the right time.
The common ones include:
- Launching without a complete redirect map
- Redirecting too many pages to the homepage
- Forgetting PDFs, images or old campaign URLs
- Blocking the live site with robots.txt
- Leaving noindex tags on key pages
- Changing URLs without a clear reason
- Removing pages that had backlinks
- Forgetting to update internal links
- Launching with staging URLs
- Breaking GA4 or conversion tracking
- Losing metadata during template changes
- Ignoring mobile layout problems
- Not checking Search Console after launch
The biggest mistake is assuming that a migration is finished when the site goes live. In reality, go-live is the start of the monitoring phase.
How to prioritise fixes after launch
After launch, you may find a long list of issues. Do not treat every issue as equal.
Prioritise fixes based on impact and urgency.
High priority issues include:
- Important pages returning 404 errors
- Commercial pages blocked from indexing
- Redirects failing on high-traffic URLs
- Broken forms or checkout steps
- Tracking failures on key conversions
- Canonicals pointing to the wrong domain
- Large sections missing from the sitemap
Medium priority issues include:
- Missing meta descriptions
- Minor internal link issues
- Non-critical image alt text gaps
- Template-level heading issues
- Slower but usable page templates
Low priority issues include small cosmetic problems that do not affect crawling, indexing, conversions or trust.
This is where a calm process helps. You do not need to fix everything in 1 day. You need to fix the things that can damage traffic, revenue and user experience first.
FAQs
What is a site migration SEO audit?
A site migration SEO audit is a structured review of your website before, during and after a migration. It checks URLs, redirects, metadata, content, internal links, indexation settings, analytics and technical performance. The aim is to protect organic visibility and prevent avoidable traffic loss.
When should SEO be involved in a website migration?
SEO should be involved before the new structure is agreed. If SEO only gets involved just before launch, key decisions may already be locked in. Early involvement helps protect valuable pages, reduce unnecessary URL changes and make sure developers have clear SEO requirements.
Do all old URLs need redirects?
Most old URLs should be reviewed, but not every URL needs to be kept alive forever. Important URLs with traffic, backlinks, rankings or commercial value should usually be redirected to the closest relevant new page. Low-value URLs with no useful replacement may be handled differently.
How long does it take for rankings to settle after a migration?
It depends on the size of the site, the scale of the changes and how cleanly the migration is handled. Some fluctuation is normal while search engines recrawl and reprocess URLs. For many websites, the first few weeks are the most important monitoring period.
Should you change URL structure during a redesign?
Only change URLs when there is a strong reason. Cleaner URLs can help, but unnecessary changes add risk. If a URL already ranks, gets traffic and supports conversions, ask whether changing it is really worth it.
What should be checked after go-live?
After go-live, check redirects, indexation, robots.txt, canonicals, sitemap coverage, tracking, forms, navigation, page speed, mobile usability and Search Console errors. You should also compare organic performance against your pre-launch benchmark.
Can a migration improve SEO?
Yes, if it is handled properly. A migration can improve site speed, structure, content quality, internal linking and UX. But the benefits only appear if the migration protects existing SEO value while fixing what was holding the old site back.
Make your migration boring, controlled and commercially safe
A good site migration should feel controlled, not dramatic. The best migrations are usually the boring ones. The launch happens, redirects work, tracking records clean data, users find what they need and search engines understand where everything moved.
That does not happen by accident.
You need a pre-launch audit, a proper redirect map, careful staging checks, clean tracking, launch day QA and post-go-live monitoring. You also need people who can connect the technical detail to the commercial impact.
If you are planning a redesign, CMS move, domain change or wider rebuild, speak to Totally.Digital before launch. Their team can help you protect organic visibility, reduce migration risk and build a website that performs better once it goes live.
Get in touch with Totally.Digital to plan your site migration SEO audit before small issues turn into expensive ranking drops.