The Complete Guide to SEO for Website Migrations: How to Preserve Rankings During Domain and Platform Moves

Types of Website Migrations and Their Risks

Migration types:

1. Domain migration (A.com → B.com)
2. HTTP to HTTPS migration
3. Platform migration (WordPress → Shopify)
4. URL structure restructuring (/blog/post → /articles/post)
5. Subdomain to root domain migration

Risk levels:

Pre-Migration Preparation

Step 1: Take a Comprehensive Backup of the Current State

Must be recorded:

• All ranking keywords and their positions (export from Ahrefs)
• All backlinks (export from Ahrefs)
• Average monthly organic traffic baseline
• A list of all indexed URLs (export from GSC)

This data serves as the benchmark for evaluating performance after the migration.

Step 2: Map Old URLs to New URLs

Create a complete mapping table for every URL that needs to be migrated:

Guiding principles:

• Every old URL must have a corresponding new URL (301 redirect)
• Keep the URL structure as similar as possible (minimize the amount of change)
• Prioritize confirming high-value pages (those with a large number of backlinks)

Step 3: Validate in a Staging Environment

Before taking the new site live in production, validate the following in a staging environment:

• All pages are accessible
• All redirects are correct (test with Screaming Frog)
• Schema markup is correct (verify with the Rich Results Test)
• Internal links do not point to old URLs

Executing the Migration

HTTP to HTTPS Migration

Correct procedure:

1. Install the SSL certificate
2. Redirect all HTTP URLs to HTTPS (301 redirects)
3. Ensure canonical tags use the HTTPS version
4. Update sitemap.xml to use HTTPS URLs
5. Add the HTTPS version as a property in GSC
6. Update the tracking code for Google Analytics and GSC

Common mistakes:

• Mixed Content: the page still contains HTTP resources (images, CSS, JS)
• Redirect chains: HTTP → HTTPS → www.HTTPS (it should be a single step: HTTP → www.HTTPS)

Domain Migration

Setting up 301 redirects: Configure bulk redirects in the server configuration file:

# Nginx configuration example
server {
    listen 80;
    server_name old-domain.com;
    return 301 https://new-domain.com$request_uri;
}

The GSC domain migration tool: GSC provides a dedicated "Change of Address" tool to notify Google that you are migrating your domain.

Path: GSC → Settings → Change of Address

URL Structure Restructuring

Configuring bulk redirects with Screaming Frog:

1. Import the list of old URLs and the new URL mapping
2. Implement the 301 redirects in bulk in the server configuration file
3. Use Screaming Frog to verify that all redirects are correct

Post-Migration Monitoring

Week One: Daily Monitoring

• GSC indexing status (whether new URLs are being indexed)
• Rankings for core keywords (monitor daily)
• Number of 404 errors (GSC Coverage report)
• Redirect chain issues (Screaming Frog)

Month One: Weekly Monitoring

• Organic traffic trends compared against the baseline
• Status of backlink targets (confirm that backlinks are being 301-redirected)
• Core Web Vitals (a new platform may perform differently)

Tips for Fast Post-Migration Recovery

1. Submit the new site's sitemap in GSC
2. Use "Request Indexing" for core pages
3. Speed up the discovery of new URLs through internal linking
4. Email important backlink sources to request that they update their links to the new URLs

Conclusion

Website migration is a high-risk operation, and thorough up-front preparation is the single most important risk-control measure. Implementing 301 redirects properly, using GSC's Change of Address tool, and establishing close post-migration monitoring are the keys to minimizing traffic loss.