A site migration is the process of moving a website from one platform, host, technology stack, or domain to another. Migrations vary in scope from minor (changing hosting providers while keeping everything else the same) to major (rebuilding a site from scratch on a different CMS while changing the URL structure).

Common types of site migration

Hosting migration. Moving from one host to another while keeping the same platform, code, and URLs
Platform migration. Moving from one CMS or platform to another (e.g., Squarespace → WordPress, Webflow → Astro)
Domain migration. Changing the primary domain (e.g., oldname.com → newname.com)
HTTPS migration. Moving a site from HTTP to HTTPS
URL structure migration. Changing how pages are organized in URLs (e.g., /blog/post-name → /articles/2026/post-name)
Redesign with structural change. Visually rebuilding while changing the underlying HTML, navigation, or content hierarchy

A single migration project often combines several of these.

What is at stake

Migrations affect:

Content fidelity. Whether text, images, formatting, and layouts survive the move
Search rankings. Whether existing organic traffic continues to land on the new site
Inbound links. Whether external links to the old site continue to work
User accounts and data. Whether logged-in users, comments, and saved data carry over
Email and DNS. Whether email service continues uninterrupted
Integrations. Whether forms, analytics, marketing tools, and ecommerce continue to function

A poorly executed migration can result in lost traffic, broken pages, and reduced search rankings that take months to recover.

A typical migration sequence

Most migrations follow a similar pattern:

Audit the existing site. Catalog URLs, content, redirects, integrations, traffic patterns, and known issues
Define the new site’s structure. URL scheme, content model, design, technology stack
Map old URLs to new URLs. Required for redirect planning
Build the new site. In a staging environment that does not affect the live site
Migrate content. Programmatically where possible; manually where not
Test on staging. Review every page type, form, integration, and edge case
Set up redirects. 301 redirects from every old URL to the corresponding new URL (or a relevant page if the content was removed)
Cut over. Update DNS, switch the live site, monitor for errors
Verify. Check that redirects work, search rankings hold, integrations function, and analytics continue
Monitor. For weeks to months, search rankings can take time to stabilize after a migration

SEO considerations

Search engines need to understand that the old URLs have moved to new URLs. Key practices:

301 redirects from every old URL to its new counterpart
Updated sitemap submitted to Google Search Console
Updated canonical tags to reflect the new URL structure
Preserved metadata (titles, descriptions, structured data) where it was working
Internal links updated to point to new URLs rather than relying on redirects

If URL structure changes, ranking volatility for several weeks is common. If URLs stay the same, impact is usually minimal.

Common migration challenges

Custom blocks and platform-specific components. Content built in proprietary editors often does not export cleanly
Forms. Form configurations rarely transfer; they typically need to be rebuilt
Embedded content. Galleries, accordions, and tabs may need manual reconstruction
Membership and ecommerce data. Customer accounts, order history, and saved payment methods may require custom export and import
DNS and email coordination. Mail can be disrupted if DNS is changed without preserving MX records
Tracking continuity. Analytics tags, conversion pixels, and event tracking need to be re-installed and verified

Migration tools

Several categories of tools assist migrations:

Platform-specific exporters. Built into the source platform (Squarespace XML export, WordPress eXtended RSS)
Format converters. Convert exports into other formats (HTML to Markdown, XML to JSON)
Crawlers and scrapers. Extract content from sites without good export options (Screaming Frog, custom scripts)
Bulk redirect tools. For generating and managing 301 redirect mappings
Visual diff tools. For comparing old and new site rendering during QA

Common misconceptions

“A migration is mostly a content move.” Content is one part. Redirects, integrations, DNS, and SEO continuity are equally critical.
“Search rankings always drop after a migration.” They can, but a well-planned migration with thorough redirects often preserves or improves rankings.
“You can migrate and redesign in one step without risk.” Combining a platform change with a major URL or content change increases the chance of ranking volatility.