Site Migration

What Counts as a Site Migration?

Site migration is one of the highest-stakes activities in SEO. According to SEMrush, nearly half of all site migrations result in a temporary traffic drop of 10-30% (SEMrush, 2024). Some never recover. The stakes are real, but migrations are often necessary for growth.

A "migration" includes any of these changes:

Types of Site Migration

The guiding principle for every migration: every old URL must point to an equivalent new URL via 301 redirects. No orphaned pages. No broken links. No lost authority.

Pre-Migration Checklist

The work you do before the migration determines whether it succeeds or fails. According to Screaming Frog, 60% of migration failures stem from incomplete redirect mapping (Screaming Frog, 2024). Here is what to do before you flip the switch:

1. Crawl your entire current site. Use Screaming Frog, Sitebulb, or similar tools to export every URL on your site. This is your master URL list. Miss a URL and its authority disappears.
2. Export Google Search Console data. Download all indexed URLs, top queries, and click data. This becomes your baseline for post-migration comparison.
3. Map every old URL to its new URL. Create a spreadsheet with two columns: old URL and new URL. Every single page must have a destination. If a page is being removed, redirect it to the most relevant surviving page.
4. Audit your backlink profile. Use Ahrefs or Moz to identify your most linked-to pages. These pages carry the most authority. Their redirects must be 100% correct.
5. Document current rankings and traffic. Take snapshots of rankings for your top 50-100 keywords. Record organic traffic by page. This is your recovery target.
6. Test on staging first. Build the new site on a staging environment. Crawl the staging site to verify all internal links, canonical tags, meta robots, and schema markup work correctly.
7. Prepare your XML sitemap. Have a new sitemap ready with all new URLs. You will submit this to Search Console immediately after migration.

Redirect Mapping: The Most Critical Step

301 redirects tell search engines that a page has permanently moved to a new URL. They pass approximately 90-99% of link equity to the destination URL (Moz, 2024). Getting redirects right is the single most important factor in migration success.

Common redirect mistakes to avoid:

• Redirecting everything to the homepage. This is the most common and most destructive mistake. Google treats blanket homepage redirects as soft 404s, meaning all the page-level authority is lost.
• Using 302 (temporary) instead of 301 (permanent). A 302 tells Google the old URL might come back. It does not pass full link equity.
• Redirect chains. A redirects to B, which redirects to C, which redirects to D. Google follows up to 5 hops but each hop loses a small amount of authority. Keep it to one redirect per URL.
• Forgetting image and PDF URLs. If images and documents have earned backlinks, those URLs need redirects too.

Migration Day: The Launch

When you are ready to go live:

1. Deploy during low-traffic hours. Choose a Tuesday or Wednesday morning (your timezone). Never migrate on a Friday. You need business days to monitor and fix issues.
2. Implement all 301 redirects simultaneously. Every old URL must redirect the moment the new site goes live.
3. Submit the new XML sitemap to Google Search Console. Add the new site property (if the domain changed) and submit immediately.
4. Use the Change of Address tool in GSC (for domain changes). This tells Google directly that your site has moved.
5. Verify robots.txt. Make sure nothing on the new site is accidentally blocked from crawling.
6. Check canonical tags. Every page should have a self-referencing canonical pointing to its new URL, not the old one.

Post-Migration Monitoring

The first 30 days after migration are critical. Here is what to watch:

• Crawl errors in GSC. Check the Coverage report daily for the first week. Any spike in 404 errors means broken redirects.
• Index coverage.Track how many new URLs Google has indexed. Use "site:yourdomain.com" to monitor index count.
• Organic traffic trends. A 10-20% dip in the first 2-4 weeks is normal. According to a study by Ahrefs, sites with proper redirects recover 90% of traffic within 3 months (Ahrefs, 2025). A sustained drop beyond 6 weeks signals a problem.
• Keyword rankings. Track your top 50 keywords daily for the first month. Fluctuations are normal. Consistent drops indicate redirect or content issues.
• Backlink audit. Check if major backlinks are now resolving correctly to your new URLs through the redirects.

Traffic Recovery Timeline

Every migration is different, but here are typical recovery patterns based on industry data from SearchMetrics (SearchMetrics, 2024):

• HTTP to HTTPS: 1-2 weeks. Lowest risk. Google has optimized for this.
• URL restructure: 4-8 weeks. Moderate disruption while Google re-crawls and reassigns rankings.
• Platform migration: 2-4 months. Template changes affect rendering, Core Web Vitals, and internal linking.
• Domain change: 3-6 months. The hardest migration. Google must transfer all trust signals to an entirely new domain.
• Content consolidation: 3-6 months. Complex because you are merging authority from multiple sources.

If you have not recovered to 90% of pre-migration traffic within 6 months, something is fundamentally wrong with your redirect mapping, content parity, or technical setup.