Site Migration

Overview

A site migration covers any substantial change to a website, such as moving to a new domain, restructuring URLs, switching CMS or hosting platforms, or shifting from HTTP to HTTPS. Unlike a simple design tweak, the addresses, structure, and signals that search engines have come to recognize all change at once, which puts the accumulated search rankings and inbound traffic at serious risk. The essential challenge, therefore, is not the technical move to a new environment itself, but transferring the existing SEO value to the new location without loss.

Types

Site migrations are categorized by what is changing. Common examples include a protocol switch from HTTP to HTTPS, a change of domain name (including moving from .com to a country-specific domain), an overhaul of URL and information structure, a site redesign, site consolidation that merges subdomains into subfolders, and a switch of CMS, platform, or hosting provider. Google organizes these into two broad cases: moves where the URLs change, and moves where the URLs stay the same, such as a hosting change or an HTTPS transition.

Required Steps for Moves with URL Changes

For migrations where URLs change, Google recommends server-side permanent redirects, preferably using the 301 or 308 HTTP status codes. Start by building a mapping table of old URLs to new URLs, then redirect every old URL to its corresponding new URL. Google explicitly advises keeping redirects in place "for as long as possible, generally at least 1 year," which is the time search engines need to move all signals, including link reassessment and recrawling, to the new URLs.

Alongside the redirects, you should announce the move with the Search Console Change of Address tool. This tool prioritizes crawling and indexing of the new site, transfers signals from the old site to the new one, and tells Google to prefer the new site when determining canonical pages. Note, however, that the Change of Address tool is not needed for a move from HTTP to HTTPS. You should also submit a sitemap containing the new URLs to speed up discovery, and update all of the new site's internal links to the new URLs based on the mapping table. Small and medium sites are advised to move all URLs at once, while large sites can migrate section by section while monitoring the results.

Moves without URL Changes

When only the hosting provider changes or the site moves to HTTPS while keeping its URLs, Google recommends a staged procedure: build and test the new infrastructure first, switch DNS settings to the new host, monitor traffic on both servers, and only then shut down the old hosting. Any robots.txt blocks or noindex tags used during testing must be removed before the move begins. Verify Googlebot access with the URL Inspection tool, and lower the DNS TTL value about a week ahead so caches refresh quickly. Google explains that it is normal for "Googlebot's crawl rate to drop briefly right after launch and then recover steadily over the following days."

Risks and Rationale

The biggest risk of a migration is a drop in traffic and rankings. External SEO sources advise expecting an initial decline in rankings and organic traffic for at least three months after a migration. Misconfigured redirects can create redirect chains (a sequence of redirects passing through intermediate steps) or broken links, which in turn break existing backlinks so that the link equity those pages held fails to pass to the new pages. Indexing gaps, where pages are never reindexed at their new URLs, are another common failure. Some experts argue that for key backlinks it is better to ask the external site owners to update the link directly to the new URL, since this passes link equity more reliably than relying on 301 redirects alone. Tools such as Ahrefs or Semrush are recommended for identifying your most valuable pages and backlinks in advance, and for tracking keyword ranking changes after the move.

Execution Checklist

• Before the move: collect a full list of existing URLs along with key pages and backlinks, and build a one-to-one mapping table of old URLs to new URLs.
• Before the move: build and test the new site in a staging environment, and prepare to remove any test-time robots.txt blocks and noindex tags.
• Before the move: lower the DNS TTL value about a week ahead (for moves without URL changes).
• During the move: set 301 permanent redirects on all existing URLs based on the mapping table. Small and medium sites should move all at once.
• During the move: update all internal links to the new URLs, and check for redirect chains and broken links.
• During the move: submit the new sitemap to Search Console, and if URLs change, announce the move with the Change of Address tool (except for HTTP to HTTPS).
• After the move: monitor the index coverage report, the sitemap report, and search performance, and track ranking changes.
• After the move: keep redirects in place for at least one year, and shut down the old hosting only after its traffic has dropped to zero.

References and Sources

• Google Search Central — Site moves with URL changes
• Google Search Central — Site moves without URL changes
• Google Search Console Help — Change of Address tool
• Site Migration SEO Checklist — migration types, risks, and backlinks