A website migration SEO project makes most owners nervous for one reason: the fear that the hard-won Google rankings will collapse in the process. That worry is justified, because a badly executed migration can cost visibility and revenue for weeks. The good news: with a clean plan, a migration can be carried out so that rankings are largely preserved. After a number of migrations – domain changes, HTTPS switches, relaunches, hosting moves – here is the checklist I work through myself.
When a migration is unavoidable
Not every migration is voluntary, and not every one is a mistake. Typical triggers where a migration makes sense or becomes necessary:
- New domain. Rebranding, name change, merging of brands.
- Switch to HTTPS. Standard today – if you are still on HTTP, you should change that anyway.
- Relaunch with a new structure. New design, new CMS, new URL structure.
- Hosting change. The most harmless case, as long as domain and URLs stay the same.
- Merging several sites. Two into one – the trickiest case for rankings.
The more that changes at once – domain, URLs, structure, content all together – the greater the risk. My advice: never everything at once. Overhaul the domain, design and URL structure in a single step and, if rankings drop, you can barely tell what caused it.
What actually breaks rankings during a migration
Google does not lose rankings because a site moves – it loses them because signals it previously evaluated get lost in the move. The most common causes:
Missing or wrong redirects
If old URLs run into nothing after the move (404) or redirect incorrectly, Google loses the connection between the old and new address – along with the authority built up. This is by far the most common cause of ranking drops.
Changed URL structure without mapping
A new CMS often generates different URLs. Without a clean old-to-new mapping, nobody knows which new page replaces the old one – and the redirects are missing in exactly the wrong places.
Lost content and metadata
In a relaunch, text often goes missing, title tags and meta descriptions are not carried over, the heading structure changes. Google then rates the new page as a worse version of the old one.
Technical blocks
A classic: the development site was blocked from Google via robots.txt or noindex – and that block travels along at go-live. Result: the new site disappears from the index entirely.
The checklist: before the migration
The most important part happens before anything goes live. Being thorough here saves you the cleanup afterwards:
- Pull a complete URL list. Capture all existing URLs – from the sitemap, a crawl and analytics. This list is the basis for any mapping.
- Identify the most important pages. Which URLs bring traffic and rankings? These take priority and must not be lost under any circumstances.
- Create an old-to-new mapping. Define the matching new URL for every old one. Where there is no 1:1 match, point to the thematically closest page – not blanket to the homepage.
- Write a redirect plan. Plan all redirects as 301 (permanent), not 302 (temporary). Only 301 transfers the authority.
- Take a backup. A full backup of the old site before anything happens. Without a working backup, any migration is a blind flight – why that matters generally is something I cover in WordPress maintenance: why it matters.
- Secure the development environment. Block the new site with noindex during development – but remember to remove the block at go-live.
The checklist: the migration itself
At the actual go-live, order and care are what count:
- Set up 301 redirects. Every old URL redirects permanently to its new target. No redirect chains (URL A to B to C) – always straight to the final destination.
- Update internal links. Switch links within the site to the new URLs, rather than routing them permanently through redirects.
- Create and submit a new sitemap. A current XML sitemap with the new URLs, submitted in the Google Search Console.
- Check noindex and robots.txt. Make sure the live site is indexable and nothing blocks it by accident.
- Consolidate HTTPS and redirects. Everything runs consistently through one variant (with or without www, always HTTPS). No duplicate versions.
The checklist: after the migration
After go-live the monitoring phase begins. The first days and weeks decide whether the migration was clean:
| Check | When | What to watch |
|---|---|---|
| Test redirects | Immediately | Sample of important old URLs – do they land correctly via 301? |
| Search Console | Immediately + ongoing | Submit new sitemap, watch indexation and crawl errors |
| 404 errors | First days | Check the error log, redirect any missed URLs afterwards |
| Rankings & traffic | 2–6 weeks | Slight fluctuations are normal, a lasting drop is a warning sign |
| Load time | First week | The new environment should not be slower than the old one |
Important: a short dip in the first one to two weeks is normal – Google has to re-crawl and re-evaluate the new structure first. Only if traffic fails to recover after several weeks is there a real problem. Then it is a matter of going through redirects and indexation systematically.
Special case: domain change
Moving to a new domain is the trickiest case, because the address itself changes – not just individual URLs. Google evaluates authority per domain, and in a change this authority has to be transferred to the new domain. On top of the 301 redirects for every single URL, the Google Search Console offers the „Change of Address” tool for this, which reports the move officially. Use it – it noticeably speeds up the re-evaluation.
It is also important not to give up the old domain too soon. Keep it active, redirects and all, for at least a year, better longer. External links pointing to the old address only keep working as long as the redirect exists. Cancel the old domain after three months and you lose exactly the backlink authority that makes up a large part of the ranking.
How I monitor the migration
A migration without measurement is a matter of luck. For me, these tools belong to every migration:
- A crawler for the before-snapshot. Crawl the whole site before the move to have all URLs, title tags and meta descriptions as a reference. That way, after go-live, you immediately see what is missing.
- Google Search Console. The central tool – for the new sitemap, the indexation reports, the crawl errors and, in a domain change, the change of address.
- A redirect checker. After the move, test a sample of the most important old URLs: does a clean 301 land everywhere straight on the right target, with no chain and no 404?
- A rank and traffic watch. Observe how the most important keywords and organic traffic develop over several weeks, to tell a normal dip from a real drop.
This monitoring is not a one-off action on moving day but stretches over several weeks. That is exactly why a migration is not a five-minute job but a supervised process – and a good moment to think ongoing care in at the same time.
Typical mistakes I see again and again
- Redirecting all old URLs to the homepage. Convenient, but harmful. Google treats such mass redirects like a soft 404 and transfers no authority. Every URL needs its matching target.
- 302 instead of 301. A temporary redirect tells Google „this is only for now” – the authority stays stuck with the old URL.
- Forgetting to remove noindex. The new site goes live but stays blocked from Google. Unnoticed for weeks, because the site works – just not in the index.
- Sitemap not updated. Google keeps following the old sitemap and only finds the new URLs with a delay.
- Migrating on a Friday afternoon. If something jams after go-live, the weekend is the worst time for troubleshooting.
Precisely because a migration brings many technical details together, it is a good moment to set the site up cleanly at the same time. If you are migrating anyway, it pays to lay the foundation professionally – whether as pure web development or with follow-up website care and maintenance, so the new site stays looked after.
Conclusion
A website migration does not have to cost rankings – if it is planned rather than improvised. The key lies in three things: a complete old-to-new mapping, clean 301 redirects without chains, and an indexable live site with a current sitemap. Capture the URLs beforehand, keep the order during the move and monitor systematically afterwards, and you almost always come through without lasting loss. A short dip in the first weeks is normal; a lasting drop is nearly always a technical fault that can be fixed. Never schedule the migration for a Friday afternoon – give yourself time for the checks.
Facing a domain change, relaunch or hosting move and do not want to risk the rankings? Write to me via the contact form – I will handle the migration or guide your team so the redirects and indexation are right from the start.
