SEO Website Migration: Step-by-Step Guide to Keeping Your Traffic

Migration types and their risks

Before kicking off the process, it is important to understand which type of migration you are dealing with — that determines the scope of preparation and the potential impact on your rankings.

A brief overview of each type:

• Redesign without URL changes — the safest option. Only the visual layer changes; the URL structure stays intact. Risk is minimal.
• HTTP → HTTPS — relatively safe when all HTTP variants have correct 301 redirects in place. Without redirects: content duplication and a rankings dip.
• URL structure change — medium risk. Requires a full URL mapping and a 301 for every changed slug.
• CMS change (e.g. WordPress → OpenCart) — medium-to-high risk due to potential URL changes, different canonical tag handling, and metadata structure differences.
• Site merger — a complex case: you need to decide which domain stays the primary one and migrate all assets to it.
• Domain change (rebranding) — the riskiest type. Even with perfect redirects, Google re-crawls the site from scratch, causing a temporary dip for 2–6 weeks.

Pre-migration checklist: what to verify before you start

Most post-migration problems stem from insufficient preparation. This checklist is the minimum you need to complete before any significant site change. A thorough SEO audit before migration significantly reduces the risk.

URL mapping: old address → new address

URL mapping is a correspondence table between old and new addresses. Without it, there is no way to set up redirects correctly. It is especially critical for large sites with hundreds or thousands of pages.

How URL mapping works in practice:

1. Crawl the old site with Screaming Frog to get the full URL list.
2. Open the list in Google Sheets. Add columns: old_url, new_url, redirect type, priority.
3. Filter out pages with 404 status codes, duplicates, and zero-traffic pages that do not need migrating.
4. For the highest-traffic pages (top 20%) — map manually. The rest can be handled automatically with slug-transformation rules.
5. Verify that every old_url has a corresponding new_url — no gaps.

301 redirects: the plan and common mistakes

A 301 redirect is the primary tool for passing SEO equity from old URLs to new ones. Properly configured redirects preserve up to 99% of PageRank (per Google). But even a small configuration mistake and you start losing rankings.

The most common redirect mistakes:

• Redirect loop (A→B→A) — browsers and search engines get an infinite cycle. The site becomes inaccessible.
• Redirect chain (A→B→C→D) — every extra hop erodes PageRank. The maximum should be one hop: old → new.
• 302 instead of 301 — a temporary redirect does not pass SEO equity. Use 301 for permanent changes.
• Forgotten HTTP variants — after moving to HTTPS, teams often forget redirects from http:// and http://www. All four variants must redirect to the canonical HTTPS version.
• Missing redirects for link-heavy pages — especially dangerous for pages with backlinks. Without a redirect the entire link juice is lost.

According to Google, a 301 redirect passes "almost all" SEO equity. However, chains of 3 or more hops can cause Googlebot to stop following the redirect chain entirely.

9 steps of SEO migration: a step-by-step guide

Below is the complete sequence of actions for a full SEO migration. Steps are grouped by phase: preparation, execution, and verification.

Step 1. Pre-migration: crawl and backup

Run a full crawl of the current site in Screaming Frog. Save the URL list, status codes, metadata, and page titles. Take a complete backup of the database and site files.

Step 2. Record current rankings and traffic

In Google Search Console, review rankings over the last 3 months. In GA4 — traffic by page. Save this data as a baseline for comparison after the migration. Without it you cannot tell whether the migration succeeded.

Step 3. URL mapping

Build a correspondence table of old_url → new_url for every page that will change address. Prioritise pages with the highest traffic and the strongest rankings.

Step 4. Redirect plan and implementation

Based on the URL mapping, configure 301 redirects. Confirm there are no chains or loops. Verify using Screaming Frog in List Mode: load all old_url values and confirm each returns a 301 pointing directly to the new_url.

Step 5. Internal links update

Replace all internal links with the new URLs directly in the code or database. Do not rely on server-level redirects for internal links alone — it creates unnecessary load and slows down crawling. For more detail on technical link health, see our article on technical SEO audit.

Step 6. Sitemap and robots.txt

Update sitemap.xml so it contains only the new URLs — remove any old addresses. Review robots.txt: confirm new URLs are not blocked. Pay special attention to any Disallow directives left over from the staging environment.

Step 7. Canonical tags

Verify that canonical tags point to new URLs, not old ones. A canonical pointing to the old URL tells Google the new page is a duplicate. For an in-depth look, see the article on canonical tag errors and best practices.

Step 8. Google Search Console

For a domain change: add the new domain as a separate property in GSC and use the "Change of Address" tool. For other migration types: submit the updated sitemap.xml. Request re-crawling of key pages via "URL Inspection".

Step 9. Post-migration monitoring

The first 48 hours are critical. Watch for 404 errors in GSC, traffic drops in GA4, and indexation of key pages. After that — scheduled weekly checks for 3 months.

Post-migration checklist: monitoring after the move

Migration success is not determined on launch day — it is determined in the weeks that follow. Here is what to monitor and when.

Pay special attention to the 404 error count in the first 48 hours. A surge in new 404s signals that part of the URL mapping did not work. Fix it immediately.

Typical mistakes that cost you traffic

Even experienced teams make these mistakes. It is better to know about them in advance.

1. Launching without a staging test

Test the full migration process on a staging server before going live on production. Without a test run you risk hitting unexpected issues at exactly the moment real users are on the site.

2. Leaving content live on both domains

After a domain change, the old site must either be blocked in robots.txt or set to redirect immediately to the new domain. If both domains serve the same content, Google will index both and dilute your link equity.

3. Ignoring internal links

Server-level 301 redirects are not a substitute for updating internal links in the code or database. Old internal links slow down crawling and can cause Googlebot to follow redirect chains instead of landing directly on the final URL.

4. Not updating external profiles

After changing URLs or the domain, update links in: Google Business Profile, social media, partner sites (where possible), email signatures, and advertising accounts.

5. Switching off GSC monitoring after the initial check

Regular GSC monitoring is mandatory for the first 3 months after migration. Some issues surface weeks later — for example, Google may re-crawl the old domain after 4–6 weeks and discover 404s where everything previously worked.

For thorough technical SEO after migration, we recommend running a full Google Search Console audit — it will surface any remaining indexation issues.

For official guidance, see Google's documentation on moving a site with URL changes.

Frequently asked questions