Site Migration: The SEO and GEO Checklist to Protect Your Traffic

Why Site Migrations Are Always Scary (and Why That's Justified)

CMS overhaul, domain name change, HTTPS switch, URL restructuring, hosting provider change: every site migration is a moment where your organic traffic can swing in either direction. Executed well, a migration costs you almost nothing. Executed poorly, it can wipe out years of rankings in a matter of days.

The good news: nearly all post-migration traffic losses come from a small, well-documented set of avoidable mistakes. The checklist below covers all three phases (before, during, after) and adds a layer most SEO guides still ignore in 2026: keeping your visibility intact across AI engines (ChatGPT, Perplexity, Google AI Overviews).

A temporary 10-20% traffic dip in the 2-4 weeks following go-live is normal — Google needs to re-crawl and re-evaluate every URL. A drop beyond 30%, or one that persists past 6 weeks, almost always signals an identifiable technical error.

The Migration Types That Trigger This Checklist

• Domain name change: acquisition, rebrand, merger — the highest-risk scenario, since it touches your entire domain authority.
• CMS or framework overhaul: moving to a headless CMS, a React/Next.js framework, or the reverse — often comes with silent changes to rendered HTML.
• HTTP → HTTPS switch: rarer today, but still common on older sites that never migrated.
• URL restructuring: silo changes, adding/removing subfolders (/blog/ to /articles/, for example).
• Hosting or server change: indirect SEO impact via load speed and uptime during the switch.

Each type carries a different risk level, but the checklist structure stays the same.

Before the Migration: Freeze Your Baseline

You can't measure a loss — or a recovery — without a precise reference point before you touch anything.

1. Export 16 months of Search Console data (clicks, impressions, position, CTR by page and query) — GSC only retains 16 months of history, so archive it before it disappears.
2. Crawl the entire current site (Screaming Frog, Sitebulb, or equivalent) to list every indexed URL, its status, canonical tags, and internal linking.
3. Identify your traffic and backlink pages: cross-reference GSC data with a backlink tool to find the URLs carrying the most authority — these are the ones you can't afford to lose.
4. Document your current SEO configuration: robots.txt, XML sitemap, structured data (schema.org), title/meta tags, hreflang if the site is multilingual.
5. Freeze URLs that already perform: where possible, keep the same URL structure for pages that already rank well. Every URL change is one more redirect, one more risk.

The 301 Redirect Map: The One Piece That Decides Everything

This is the single most decisive step of the entire migration. Every indexed old URL must point to its new destination through a 301 redirect — never a redirect chain, never a loop.

Three non-negotiable rules:

• One redirect = one 1:1 match to the most semantically relevant page. Redirecting everything to the homepage ("disguised soft 404") destroys the SEO value of every individual URL.
• Zero redirect chains: A → B → C slows crawling and dilutes link equity. Always redirect straight to the final destination.
• Keep redirects live for at least 12 months, ideally permanently — external backlinks keep pointing to old URLs for years.

For exact syntax and use cases (301 vs 302, wildcard redirects, parameter handling), our complete guide to HTTP redirects covers every scenario.

Staging: Your Last Line of Defense Before Go-Live

Before you flip to production, your staging environment needs to be invisible to every engine — Google and AI alike.

User-agent: *
Disallow: /

This blocking robots.txt, combined with a noindex tag and password authentication, prevents accidental indexing of staging. The classic mistake: forgetting to remove it at go-live, which then blocks real production. Check it first on launch day.

Launch Day: The Go-Live Checklist

1. Flip DNS and lower the TTL 24-48h before the switch to speed up propagation.
2. Activate all 301 redirects at the exact moment of cutover — not before, not after.
3. Remove the staging robots.txt block and deploy the production robots.txt.
4. Submit the new XML sitemap in Search Console.
5. If the domain name changed, use the Change of Address tool in Google Search Console — it's the only way to explicitly tell Google the old and new domains are the same site.
6. Verify canonical tags point to the new URLs, not the old ones.
7. Confirm structured data (schema.org, FAQ, breadcrumbs) is still present in the new codebase.

The Part (Almost) Nobody Checks: GEO Continuity

Every migration checklist talks about redirects and sitemaps. Very few talk about what happens to your visibility across AI engines — and that's exactly where most sites lose citations without ever noticing, because Search Console will never show you that loss.

• Re-authorize AI crawlers in the new robots.txt: GPTBot, ClaudeBot, and PerplexityBot are often missing from the "clean" robots.txt templates a new CMS generates by default. If your old site allowed them, verify they're still allowed after migration. Our 2026 robots.txt guide lists the user-agents worth tracking.
• Migrate your llms.txt file: if it pointed to URLs that changed, it silently goes stale — no engine will alert you. Check every link it contains after go-live. Our llms.txt guide explains how to structure it.
• Preserve FAQ/Q&A structured data: this is the data generative AI engines consume most easily to cite a source. A redesign that simplifies HTML "for performance" often strips this markup without anyone noticing for weeks.

Across the post-migration audits we've run in 2026 on French SaaS and e-commerce sites, one scenario keeps repeating: Google traffic drops 15-20% in the first week (normal, everyone watches this closely) — but nobody notices that citations in Perplexity and AI Overviews dropped to zero, because the llms.txt pointed to old URLs now returning 404s, and the new robots.txt, auto-generated by the CMS, had quietly dropped PerplexityBot. Result: 6-8 weeks of lost AI citations, discovered only during a dedicated GEO audit — because no standard analytics tool tracks this by default.

The First 30 Days: Post-Migration Monitoring

• Week 1: check 404 errors daily in Search Console and server logs. Every un-redirected 404 is authority loss that can still be fixed quickly.
• Days 1-28: track rankings on your 20 most important queries and traffic on your 50 highest historical-traffic pages.
• Day 28: run a second full crawl of the new site and compare it to the pre-migration crawl — this is typically when Google has finished re-discovering most of your URLs.
• Ongoing: monitor Core Web Vitals, which can silently degrade if the new codebase wasn't audited under real conditions.

A free audit right after go-live can spot redirect, robots.txt, or structured data errors in minutes — the kind that a manual check would miss.

Key Takeaways

• A 10-20% traffic dip in the first 2-4 weeks is normal; beyond 30%, or past 6 weeks, look for a technical error.
• The 301 redirect map (1:1, no chains, no loops) is the single factor that weighs most on the final outcome.
• GEO continuity (AI-crawler access in robots.txt, llms.txt, structured data) is just as critical as classic SEO continuity — and far less monitored.
• The first 28 days post-migration need daily checks, not monthly ones.

FAQ — Site Migration and SEO/GEO

How long does it take to recover traffic after a migration?

Generally 4 to 8 weeks for a well-executed migration, the time it takes Google to re-crawl and re-evaluate every URL. A poorly prepared migration (missing redirects, blocking robots.txt) can take several months — or never fully recover if the errors are never fixed.

Do I really need to redirect every single old URL?

Any URL that's indexed or receiving traffic/backlinks, yes. URLs that were never indexed and never received traffic can safely return a clean 404 — but when in doubt, a 1:1 redirect remains the safest option.

Does changing your domain name mean losing your accumulated authority?

Not if you use Search Console's Change of Address tool and have 301 redirects properly in place. Google then progressively transfers authority from the old domain to the new one over several weeks.

Why did my citations in ChatGPT or Perplexity disappear after my migration even though my Google traffic is stable?

That's the classic GEO scenario: traditional SEO can look preserved while robots.txt now blocks an AI crawler, or llms.txt points to dead URLs. These losses don't show up in any standard analytics tool — a dedicated audit is the only reliable way to detect them.

Should redirects stay in place forever?

Ideally yes for high-traffic or high-backlink URLs. At minimum, keep them active for 12 months — most external sites linking to you will never update their links.

Planning a migration, or just wrapped one up? Run a SeAudit audit to check in minutes whether your redirects, robots.txt, and GEO visibility actually survived the move.