How to Audit an Entire Website After an SEO Migration and Catch Ranking-Critical Issues

September 13, 2026

A website migration can improve performance, design, technology, and scalability—but it can also cause significant organic traffic losses if important SEO signals are accidentally changed or removed.

A post-migration SEO audit is therefore more than a routine technical check. It is a systematic review of the entire website to identify anything that could prevent search engines from crawling, indexing, understanding, or ranking the migrated site.

The sooner ranking-critical issues are identified, the easier they are to fix.

Here is how to perform a comprehensive SEO migration audit after a website move.

What Is an SEO Migration Audit?

An SEO migration audit evaluates a website after a migration to determine whether its important search engine signals were preserved.

Website migrations can include:

Domain changes
URL structure changes
Platform migrations
Website redesigns
HTTP-to-HTTPS migrations
CMS changes
Hosting changes
International site migrations
Major information architecture changes

Regardless of the type of migration, the objective is the same: make sure search engines can still access and interpret the website correctly.

A post-migration audit should compare the new website against the previous version wherever possible.

Start With Organic Traffic and Rankings

Before investigating technical details, determine whether the migration caused measurable changes in performance.

Compare pre-migration and post-migration data for:

Organic clicks
Organic impressions
Rankings
Organic sessions
Conversions
Revenue
Indexed pages
Top landing pages

Look at both the overall website and individual URLs.

A relatively stable total can sometimes hide serious problems. For example, a few high-performing pages might retain their traffic while dozens of important URLs lose visibility.

Pay particular attention to pages that previously generated significant organic traffic or revenue.

Crawl the Entire Migrated Website

Run a comprehensive crawl of the new website to understand what search engines can currently access.

Look for:

Broken links
4xx errors
5xx errors
Redirect chains
Redirect loops
Incorrect canonical tags
Missing title tags
Missing meta descriptions
Duplicate URLs
Orphan pages
Incorrect status codes
Blocked resources
Indexability issues

Compare the crawl with a crawl of the old website if one is available.

This comparison can reveal pages and signals that disappeared during the migration.

Check URL Redirects

Redirects are one of the most important parts of website migration SEO.

If URLs changed during the migration, important old URLs should generally redirect to their corresponding new destinations.

For example:

/old-product/

should redirect to:

/products/new-product/

rather than simply sending users to the homepage.

Audit your old URL list against the new URL structure.

Look for:

Missing redirects
Incorrect redirect destinations
302 redirects where permanent redirects are appropriate
Redirect chains
Redirect loops
Redirects pointing to irrelevant pages
Large groups of old URLs returning 404 errors

Don't only test a handful of URLs manually. Use the complete historical URL list whenever possible.

Verify Canonical Tags

Canonical tags can change during migrations, sometimes unintentionally.

Check whether important pages have canonical tags pointing to the correct preferred URLs.

Common migration mistakes include:

Canonicals pointing to the old domain
Canonicals pointing to HTTP versions
Self-referencing canonicals missing from important pages
Canonicals pointing to unrelated pages
Multiple canonical declarations
Canonicals referencing redirected URLs

A canonical URL should accurately represent the preferred version of the page.

Check Robots.txt

Review the migrated site's robots.txt file carefully.

A staging environment may have used directives designed to block crawling, and those directives can accidentally remain in production.

Look for rules that unintentionally block:

Important directories
Product pages
Category pages
CSS and JavaScript resources
Images
Search-critical content

A single overly broad robots.txt rule can prevent search engines from accessing large portions of a website.

Review Meta Robots Directives

Robots meta tags should also be checked across the migrated website.

Look for important pages that accidentally contain:

noindex

or other restrictive directives.

This is particularly important when the development or staging website was configured not to appear in search results.

A migration can transfer those settings to production without anyone noticing immediately.

Prioritize pages that previously ranked or generated organic traffic.

Compare XML Sitemaps

Your XML sitemap should accurately reflect the new website.

Check that:

Important URLs are included
URLs use the correct protocol
URLs use the correct domain
Redirected URLs aren't included
Canonicalized URLs aren't unnecessarily included
Noindex pages aren't included
Broken URLs aren't included

If your site has multiple XML sitemaps, audit each one individually.

The sitemap should provide search engines with a clean list of URLs you actually want crawled and indexed.

Check Internal Links

A migration can break internal links even when redirects are working correctly.

For example, internal links might still point to:

Old URLs
Redirecting URLs
Broken URLs
HTTP versions
Incorrect subdirectories

Ideally, internal links should point directly to the final canonical URL.

Review links across navigation, category pages, content, breadcrumbs, footers, and other important site elements.

This is especially important for large websites where internal linking distributes significant amounts of authority throughout the site.

Audit Indexation

Check what Google is actually indexing after the migration.

Compare indexed URL counts and inspect important pages individually.

Look for unexpected patterns such as:

Important pages disappearing from the index
Thousands of new parameter URLs becoming indexed
Duplicate pages appearing
Staging URLs being indexed
Old URLs remaining indexed
Important categories becoming excluded
Unexpected canonicalization

Don't assume that a page being accessible in a browser means it is eligible for search visibility.

Indexability needs to be evaluated separately from accessibility.

Check Structured Data

If the previous website used structured data, make sure the migration didn't remove or break it.

Review relevant schema markup for:

Products
Reviews
Organizations
Breadcrumbs
Articles
Local businesses
Events
Other applicable entities

Check whether structured data still references the correct URLs, names, images, products, and other properties.

A redesign or CMS migration can easily remove schema templates that were previously generating useful structured data.

Review International SEO Signals

For multilingual or multinational websites, audit international SEO implementation carefully.

Check:

hreflang annotations
Language codes
Country targeting
Canonical relationships
Alternate URLs
Internal links between language versions
XML sitemap implementation

A migration can introduce incorrect language or country relationships that cause the wrong version of a page to appear in search results.

Test Page Speed and Core Technical Performance

A migration may change hosting, code, JavaScript, image delivery, caching, or third-party integrations.

Measure the new website's performance after launch.

Check:

Core Web Vitals
Largest Contentful Paint
Interaction to Next Paint
Cumulative Layout Shift
Server response time
Mobile performance
Image loading
JavaScript execution

Performance problems may not immediately appear as ranking losses, but they can create poor user experiences and technical problems that deserve attention.

Audit High-Value Pages First

When a migration causes a traffic decline, don't attempt to manually inspect every page before fixing obvious high-impact problems.

Prioritize:

Pages with the highest historical organic traffic
Pages generating conversions or revenue
Pages with valuable backlinks
Important category and service pages
High-ranking informational content
Homepage and major navigation pages

If a critical landing page has become noindex, canonicalized incorrectly, or redirected to an irrelevant URL, fixing it should take priority over minor metadata issues elsewhere.

Compare the Old and New Websites

One of the strongest approaches to post-migration auditing is direct comparison.

Build an old-versus-new URL dataset containing:

Old URL
New URL
HTTP status
Redirect destination
Canonical URL
Indexability
Title
H1
Organic traffic
Organic rankings
Internal links

This makes it easier to identify exactly what changed.

Instead of asking, "Why did traffic drop?" you can investigate specific URL-level differences.

Monitor the Site After Fixes

An SEO migration audit shouldn't end after the first crawl.

Continue monitoring:

Organic traffic
Rankings
Search impressions
Indexed pages
Crawl errors
Server errors
Redirect behavior
Sitemap status
Search Console notifications

Some migration problems only become visible after search engines recrawl and process the new website.

Final Thoughts

A successful migration isn't simply a website that launches without errors. It is a website that preserves the SEO signals, URLs, content, internal links, and technical accessibility that supported its previous organic performance.

A thorough SEO migration audit should therefore examine redirects, crawlability, indexability, canonicals, XML sitemaps, internal links, structured data, international SEO, performance, rankings, and organic traffic.

Most importantly, compare the old and new websites rather than auditing the new site in isolation.

That comparison can reveal ranking-critical changes that a standard technical SEO audit might miss—and gives you a much clearer path toward restoring or improving organic visibility after migration.

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