301 Redirects and Domain Migrations: SEO Guide

## Why Domain Migrations Are High-Risk SEO Events Changing your domain name — whether moving from oldcompany.com to newcompany.com, upgrading from http to https, or consolidating multiple domains — is one of the most technically complex and highest-risk operations in SEO. Done correctly, you can migrate a site with minimal ranking loss. Done incorrectly, you can lose 30-70% of organic traffic and spend 6-18 months recovering. The 301 redirect is the primary technical mechanism for a domain migration, and understanding how Google processes redirects is essential for protecting your rankings. ## How 301 Redirects Work A 301 redirect is an HTTP status code that tells browsers and crawlers: "This resource has permanently moved to a new URL." When Google's crawler follows a 301, it understands that the destination URL should inherit the indexing and authority signals from the source URL. Contrast this with a 302 redirect (temporary), which signals that the original URL should remain indexed and the authority should not be transferred. Using 302s for domain migrations is a common mistake that preserves the old site in Google's index rather than transferring authority to the new domain. The key mechanics of 301 redirect authority transfer: - **Link equity passes**: Roughly 90-99% of the backlink value from the old URL transfers to the new URL via a 301. Google confirmed in 2016 that 301 and 302 redirects pass full PageRank — this corrected years of SEO conventional wisdom that assumed some "link juice" was lost in redirects. - **Index update is gradual**: Google does not immediately remove the old URLs from its index. It processes the redirect, validates the new destination, and gradually replaces old URLs with new ones. This takes weeks to months for large sites. - **Canonicalization follows**: Once Google processes the redirect chain and determines the new canonical URL, it updates its internal representations accordingly. ## Planning a Domain Migration ### Step 1: URL Mapping Before touching any server configuration, create a complete URL mapping that matches every old URL to its corresponding new URL. For a 1:1 domain change (oldsite.com/page → newsite.com/page), this is straightforward. For domain migrations that involve URL restructuring, every URL must be mapped individually. Tools to export your current URL inventory: - Google Search Console → Coverage report - Screaming Frog crawl - Sitemap XML export ### Step 2: Prepare the New Site The new site must be fully functional before you redirect traffic to it. Test on staging: - All content is present and correct - Internal links use the new domain - Canonical tags point to the new domain - SSL certificate is installed and functional - Page speed is acceptable ### Step 3: Update Google Search Console Add both the old and new domains to Google Search Console as separate properties. The Change of Address tool under Settings is specifically designed for domain-level migrations. Submit it before executing redirects. ### Step 4: Implement Redirects Server-Side Implement 301 redirects at the server level, not via JavaScript or meta refresh tags. JavaScript redirects are not processed by Google's crawler reliably. Meta refresh redirects are treated as 301s but introduce unnecessary delays. For Apache (in .htaccess): ``` RewriteEngine On RewriteRule ^(.*)$ https://newdomain.com/$1 [R=301,L] ``` For Nginx: ``` server { listen 80; server_name olddomain.com; return 301 https://newdomain.com$request_uri; } ``` ### Step 5: Update Backlinks and References After the migration, update as many backlinks as possible to point directly to the new domain. While 301s pass authority, a direct link is always stronger than a redirected one. Prioritize: - Your own other properties (social media, other websites) - High-authority referring domains where you can request updates - Business directory listings ### Step 6: Monitor and Verify Use Google Search Console to monitor: - Crawl coverage (old vs. new URLs being indexed) - Impressions and clicks (expect a temporary dip) - Any crawl errors on the new domain - Index status of old URLs (they should gradually disappear) ## Common Domain Migration Mistakes **Implementing redirects before the new site is ready.** Users and crawlers hit the redirect, land on an unfinished page, and bounce. This creates negative behavioral signals during a critical period. **Using 302 (temporary) instead of 301 (permanent) redirects.** This keeps the old domain indexed alongside the new one, diluting authority between two versions. **Redirecting everything to the homepage.** All old URLs should redirect to their direct equivalent on the new domain. Redirecting /products/widget → /homepage loses the relevance signal for that specific page. **Forgetting internal links.** Internal links on the new site that still reference the old domain create redirect chains that slow crawling and dilute link equity. **Not maintaining redirects long enough.** Some SEOs remove redirect infrastructure after 6-12 months to save server resources. Google and Bing continue crawling old URLs for 2-5 years. Maintain redirects for at least 2-3 years. ## Using TLD Comparison Tool for Migration Decisions If you are migrating to take advantage of a different TLD — for example, moving from .net to .com, or from a country domain to a global one — use our TLD Comparison Tool to model the expected SEO impact of the new TLD before committing to the migration. ## Timeline Expectations A typical domain migration produces these observable phases: **Week 1-2**: Google discovers redirects, begins processing. Ranking volatility is common. **Week 3-6**: Google crawls new domain more aggressively, starts replacing old URLs with new ones in its index. Some rankings may drop temporarily as Google recalibrates. **Month 2-3**: Most high-priority pages have been re-indexed on the new domain. Rankings begin stabilizing. **Month 4-6**: Full migration complete for large sites. Rankings should match or exceed pre-migration levels if the migration was executed correctly. **Month 6-18**: Long-tail pages fully re-indexed. Old domain URLs gradually disappear from index. ## HTTPS Migration: A Special Case Migrating from HTTP to HTTPS is a domain migration variant that every site must complete. Google confirmed HTTPS as a ranking signal in 2014, and since 2018 Chrome has marked non-HTTPS sites as "Not Secure." The HTTPS migration follows the same redirect principles, but with additional steps: - Install and configure an SSL certificate - Update all internal links to use HTTPS URLs - Update the canonical URL tags to HTTPS - Update your CDN, external scripts, and embedded content to HTTPS - Set up HSTS (HTTP Strict Transport Security) after confirming everything works ## Related Guides - Changing Your Domain Name Without Losing Rankings — End-to-end guide to domain name changes - HTTPS and SSL: The SEO Connection — Why HTTPS matters for SEO and how to implement it - Domain Authority: What It Is and How to Build It — Understanding the authority you are transferring