What is website migration? Website migration is the process of making significant changes to a website’s infrastructure, platform, URL structure, domain, or hosting environment. Common types include platform migrations (moving CMS), domain migrations (changing your web address), and hosting migrations (moving to a new server). Each type requires careful planning to avoid losing SEO rankings, functionality, or data.
Moving a website is exactly like moving house. You would not throw your belongings into a van without carefully boxing them, labelling everything, confirming the new address is ready, and having a clear plan for what to do if something goes wrong. The consequences of doing it carelessly are not just inconvenience, but the months it could take to fix things later.
The specific fear that surrounds website migrations — “our traffic dropped after migration” — is one of the most common digital marketing horror stories, and it is almost always preventable. Sites lose 80–90% of their organic traffic overnight when migrations go wrong, and documented cases show recovery taking well over a year, or sometimes not occurring at all. For an organisation that depends on organic search for enquiries, donations, or bookings, it is a year of lost revenue that a better plan would have protected.
The other side of this fear also has a cost. Organisations that defer migrations they genuinely need because the current platform is outdated, the domain has rebranded, or hosting is underperforming, are accumulating technical debt and operational limitations in exchange for the illusion of safety.
This guide covers the full migration process, step by step, with an honest treatment of SEO risks and how to manage them, a risk table, and a complete before-and-after checklist.
When do you need a website migration?
Not every change requires a migration. Understanding the legitimate triggers helps distinguish between situations that warrant the work and situations where incremental maintenance is the right call.
Common legitimate triggers for migration:
- Platform migration. The current CMS is outdated, unsupported, or cannot meet the organisation’s evolving requirements. A platform reaching the end of life is an operational risk.
- Domain migration. Rebranding, a business name change, or the consolidation of multiple domains. Domain migrations are among the highest-risk migration types and require the most careful SEO planning.
- Hosting migration. Moving to a better-performing, more secure, or more cost-effective hosting environment. If the URL structure does not change, this is the lowest-risk migration type.
- URL restructure. A redesign that reorganises the site’s page hierarchy, for example, removing subfolder prefixes, consolidating sections, or establishing a new URL convention.
- HTTP to HTTPS. Securing the site under HTTPS. This should already be complete for most sites; Google has explicitly recommended HTTPS for years and uses it as a ranking signal.
- CMS-to-CMS migration. Moving content between platforms, for example, from a legacy bespoke CMS to WordPress, Drupal, or Wagtail.
When not to migrate: if the current platform meets your operational needs, a migration adds risk without benefit. Confirm that migration is the right solution before scoping it. If the underlying problem is outdated content or poor configuration, migration is not the fix.
What are the different types of website migration?
The main types of website migration are: hosting migration (moving to a new server without changing URLs), platform or CMS migration (changing the content management system), domain migration (changing the website address), URL structure migration (reorganising page paths), and protocol migration (moving from HTTP to HTTPS). Many projects combine multiple migration types simultaneously, which compounds complexity and risk.
Step-by-step website migration process
Step 1 — Pre-migration audit and planning
This phase is the most important and the most commonly under-resourced.
What this covers: A full crawl of the existing site cataloguing every URL, page title, meta description, canonical tag, existing redirect, and internal link structure. An analytics baseline — recording current rankings, organic traffic by page, and conversion rates for all key pages — to serve as the comparison benchmark post-migration. Identification of high-value pages: which URLs drive the most organic traffic, revenue, and inbound links. These require the most careful handling. URL mapping: for every existing URL that will change, a documented mapping to its new destination. And a stakeholder alignment meeting to agree on the timeline, responsibilities, testing protocols, and the rollback plan before any migration work begins.
Client responsibilities: Provide access to Search Console, GA4, and the existing hosting environment. Sign off on the URL map before migration proceeds; once redirects are implemented, changes become significantly more expensive. Identify and brief all internal teams affected by the migration: marketing, IT, operations, and communications.
Why this phase cannot be skipped: SEO migration guidance from practitioners consistently emphasises that crawling the old site, capturing rankings, and using tools like Screaming Frog to establish a pre-migration baseline are essential for both catching issues before they go live and diagnosing problems post-migration if they occur.
Step 2 — Set up and test in a staging environment
All migration work should be done in a staging environment, which is a private, non-indexed copy of the site, before making changes to the live site. The staging environment is where problems are caught at low cost rather than discovered post-launch at high cost.
Staging testing covers every form and integration, navigation across all page types, responsive display on mobile and tablet, load speed and Core Web Vitals benchmarked in the new environment (do not assume performance will carry over from the old environment because it often does not), and an accessibility audit against WCAG 2.2 AA before go-live.
The accessibility check is frequently skipped during migrations and is frequently where problems emerge: a platform migration can change how focusable elements are rendered, how headings are structured, or how form labels are associated, all of which affect both WCAG compliance and screen reader usability.
Step 3 — SEO preparation
SEO preparation is intentionally treated as a separate step rather than embedded in the general process because it is the highest-anxiety dimension of any migration and deserves explicit, unambiguous attention.
Redirects. Every URL that changes must have a 301 redirect pointing from the old URL to its correct new destination, which is implemented before go-live, not after. Google’s own site-move documentation confirms that properly implemented 301 redirects do not cause inherent PageRank loss signals to transfer over time. What causes ranking loss is missing redirects, not having them. Avoid redirect chains (old URL → intermediate URL → new URL) and map directly to the final destination.
Google recommends keeping redirects in place for at least one year to allow ranking signals to transfer fully and for external links to update.
Sitemaps. Prepare an updated XML sitemap for the new URL structure, ready to submit to Search Console immediately after go-live.
Search Console. Prepare properties for the new domain or protocol, if changing. If the domain is changing, use Search Console’s Change of Address tool.
Internal links. Update all internal links within the site to reference new URLs at the source. Redirects handle external links pointing to old URLs, but internal links should not rely on redirects; they should be updated directly.
Canonicals and structured data. Review and update canonical tags and hreflang tags (if the site targets multiple languages or regions) to reference new URLs. Validate structured data on key pages.
Step 4 — Execute the migration
Schedule migration at a low-traffic time — off-peak hours or weekends for most organisations. This minimises the number of users affected by any immediate post-launch issues and gives the team time to monitor before normal traffic volumes resume.
Execute in the agreed sequence: DNS record changes, file transfers, database migration, CDN and cache configuration updates. Keep the old site accessible for as long as possible during cutover and do not take it down until the new site is confirmed live and functioning.
Immediately after go-live, verify all redirects are firing correctly using a site crawler. A redirect that was correct in staging may behave differently in production, and catching these issues within hours rather than days significantly limits the SEO impact.
Step 5 — Post-migration monitoring
Post-migration monitoring is the most underserved phase in most migration projects. The migration does not end at launch. It ends when the site’s organic performance has stabilised at or above pre-migration levels. For complex migrations, this monitoring period should run for at least 90 days.
First 30 days (daily review): Monitor Search Console for crawl errors, indexation issues, and manual actions. Compare organic traffic and conversions week over week against the pre-migration baseline established in Step 1. Check that all critical pages are indexed using Search Console’s URL Inspection tool. Verify that GA4 and analytics tracking are functioning correctly on the new site because migrations often silently disrupt tag configurations.
Ongoing (monthly review): Monitor Core Web Vitals in the new environment — migrations can change performance characteristics significantly. Run crawlers to identify 404 errors, redirect issues, and duplicate content introduced during migration. Track ranking positions for high-value pages against pre-migration benchmarks.
How to protect your SEO rankings during migration?
SEO ranking drops after migration are almost always caused by missing or incorrect 301 redirects, blocked crawling, lost high-value pages, or broken internal linking. With a complete URL map, correct redirects, updated sitemaps, and close post-migration monitoring, rankings can usually be preserved and sometimes improved over time.
The redirect plan is the most important SEO document in a migration
Semrush’s guidance on 301 vs 302 redirects is unambiguous: 301 redirects signal a permanent change and transfer nearly all link equity to the new URL. 302 redirects signal a temporary move and leave ranking signals associated with the old URL, which, for a migration, means those signals are not transferred. Use 301s for any permanent URL change.
The redirect plan should be a spreadsheet documenting: every old URL, every new destination, the redirect type, and the rationale. This document is also the primary diagnostic tool for issues that arise post-migration.
What causes post-migration ranking drops
- Missing or incorrect 301 redirects are the most common and most damaging cause.
- robots.txt misconfiguration or noindex tags left from staging, blocking search engines from crawling the new site.
- Removal of pages that had accumulated backlinks and organic authority without a suitable redirect to an equivalent page.
- Major content changes to previously high-performing pages are compounding the signal disruption caused by the migration itself.
- Failure to submit updated sitemaps or configure Search Console correctly for the new domain or protocol.
How long does SEO recovery take after migration?
Google’s documentation notes that for most small-to-medium sites, indexing and signal transfer after a well-handled move takes a few weeks to a few months. BrightEdge case study evidence shows that carefully executed migrations can result in organic traffic reaching nearly 200% of pre-migration levels and over 600 keywords reaching page-one positions — demonstrating that the risk is not inherent in migration itself but in poorly managed migrations.
Poorly planned migrations — particularly domain changes — can cause traffic drops of 80–90% and may take many months to fully recover. BrightEdge research shows organic search drives approximately 53% of all trackable website traffic on average, which means a failed migration can jeopardise the majority of an organisation’s inbound digital traffic.
Planning a website migration and want to make sure your SEO is protected? Butterfly’s migration process treats SEO preservation as a core deliverable, not an afterthought. Request a migration consultation.
Website migration risks and how to mitigate them?
| Risk | Likelihood | Mitigation |
|---|---|---|
| SEO ranking drop | High if unmanaged | Complete URL mapping, 301 redirects, updated sitemaps, and close monitoring |
| Data loss | Medium | Full backup of files and databases before migration; restoration tested |
| Extended downtime | Medium | Staging environment testing; phased cutover; rollback plan documented and agreed |
| Broken functionality | Medium | Comprehensive QA in staging; post-launch checks within hours of go-live |
| Analytics tracking failure | Medium | Verify GA4 and tags in staging; confirm tracking in first hours post-launch |
| Accessibility regression | Low–medium | WCAG audits in staging and re-verified on live site post-launch |
How long does a website migration take?
A simple hosting migration with no URL changes can be completed in a day. A platform migration (changing CMS) for a mid-size site typically takes 4–12 weeks, including planning, build, testing, and go-live. Full domain and URL restructures add complexity and require a longer period for SEO planning and monitoring.
Variables that extend migration timelines:
- Volume of content to be migrated and reformatted for the new platform.
- Complexity of the new platform build and any custom functionality.
- Number of integrations to be reconnected in the new environment.
- Scale of URL structure changes and the required redirect mapping.
- Stakeholder approval cycles at each phase.
If migration is part of a full website redesign or rebuild, see our website development process guide for phase-by-phase timeline guidance and our website redesign guide for context on when a migration-plus-redesign is the right strategic call.
Can you migrate your website yourself?
Simple hosting migrations that involve moving files and a database between providers with no URL changes are manageable for technically confident website owners. Platform migrations, domain migrations, or any migration that involves significant changes to the URL structure should be handled by an experienced developer. The SEO and functionality risks of errors are substantial, and the cost of recovery from a failed migration typically far exceeds the cost of professional help from the outset.
Website migration checklist
Pre-Migration
- Full site crawl completed — all URLs, metadata, redirects, and internal links catalogued
- Analytics baseline recorded — organic traffic, rankings, and conversions for all key pages
- High-value pages identified (top traffic, revenue, and backlink earners)
- URL map completed — every changing URL mapped to its new destination
- Full site backup created and restoration tested
- Staging environment built and confirmed to be functional
- All staging tests passed: forms, integrations, navigation, responsive display
- Accessibility audit completed in staging against WCAG 2.2 AA
- Performance benchmarked in the staging environment
- Rollback plan agreed, documented, and communicated to all parties
SEO Preparation
- 301 redirects implemented for all changed URLs
- No redirect chains or loops — all old URLs mapped directly to final destinations
- robots.txt reviewed — staging blocks removed; live site crawlable
- XML sitemap updated for new URL structure
- Search Console properties configured for a new domain or protocol
- All internal links updated to new URLs at the source
- Canonical and hreflang tags updated where applicable
- Structured data validated on key pages
Migration Execution
- Migration is scheduled at a low-traffic time
- DNS records updated and propagation monitored
- New hosting and CDN configuration tested
- The new site is confirmed live and functional before the old site is taken down
- 301 redirects verified with a crawler — no 404s for old URLs
Post-Migration (First 30–90 Days)
- Search Console is monitored daily for crawl errors and indexation issues
- New sitemap submitted and confirmed indexed
- All key pages confirmed indexed via the URL Inspection tool
- GA4 and analytics tracking verified on the live site
- Core Web Vitals checked on key page templates
- Organic traffic monitored vs baseline — anomalies investigated promptly
- Any post-launch bugs logged, prioritised, and resolved
- Accessibility re-verified on the live site
How Butterfly manages website migrations
Butterfly’s migration approach follows Google’s site-move guidance directly: complete URL mapping and redirect planning, pre-migration audit and benchmark, staging environment testing and QA, and structured post-migration monitoring through Search Console and analytics.
We work with government, healthcare, education, and not-for-profit organisations where uptime, compliance, and SEO preservation are not optional considerations. Migrations are scoped as multi-phase projects with explicit SEO deliverables, not treated as simple hosting changes where complexity is discovered mid-execution.
For organisations migrating to a new CMS platform, our web development services cover the full rebuild alongside the migration. For the hosting migration context, see our web hosting guide.
Frequently asked questions about website migration
Website migration involves making significant changes to a site’s hosting, platform, domain, or URL structure. It requires careful planning to avoid losing SEO rankings, data, or functionality during the transition.
The biggest risks are SEO ranking drops due to missing redirects or indexing errors, data loss, extended downtime, and broken functionality. All are manageable with proper planning, a staging environment, a complete URL map, and a rollback plan agreed upon before migration begins.
 Create a complete URL map before migration begins. Implement 301 redirects from every old URL to its new destination. Update sitemaps and internal links. Configure Search Console for the new domain or protocol. Monitor crawl errors and organic traffic closely for at least 30–90 days after launch.
A simple hosting migration may take a day. A full platform or domain migration typically takes 4–12 weeks, depending on content volume, URL structure complexity, technical build, and stakeholder approval cycles.
Yes. Google recommends keeping redirects in place for at least a year after a site move, and keeping the old site accessible until the new site is confirmed live and functioning. Turning off the old site prematurely before redirects are verified is one of the most common causes of avoidable ranking loss.
A hosting migration with no URL changes is manageable for technically confident users. Platform migrations, domain migrations, and major URL restructures pose significant SEO and technical risks if mishandled. Professional support is strongly recommended when organic search is an important channel.
Website migration without a plan is a business risk
The organisations that migrate successfully are not the ones with the most technical resources. They are the ones with the clearest plan, who know what every URL maps to before a single file moves, who have tested everything in staging, who have a rollback plan agreed upon before go-live, and who monitor closely enough to catch problems while they are still recoverable.
The checklist above is the plan. The step-by-step process above is the execution. The SEO section above is the insurance.
A migration done this way protects what the organisation has built in organic search, delivers the platform or infrastructure it actually needs, and launches with confidence rather than anxiety.
Move your website without the stress or the traffic drop. Talk to Butterfly about a structured, SEO-safe migration for your organisation. Get in touch.
