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Migrating a website without losing rankings – site migration SEO step by step for a platform change in 2026
What actually happens to your SEO when you change platform?
When you migrate a website, you do not just move the design – you move URLs, content and the signals Google and AI models use to understand and rank the website. That is what site migration SEO deals with: done right, you keep your organic traffic. Done wrong, you can lose a large part of it, sometimes for a long time.
Three things are at stake in every migration: your URLs, which must lead to the right place after the change via 301 redirects; your indexing – how quickly Google finds and accepts the new pages; and the authority you have built up – the value from backlinks and brand mentions that needs to carry over to the new addresses.
The key insight: the risk does not come from changing platform as such, but from how many things you change at the same time. Moving from one tool to another while keeping the domain and URL structure is low risk. Changing domain, URL structure, design and content all at once is high risk.
Risks of a website migration
You can estimate the size of the risk before you start. It comes down to which variables change – and above all how many of them change at the same time. Use the tool below to place your planned migration on a risk scale.
How risky is your migration?
Tick what applies to your planned migration. The more variables you change at once, the higher the risk – and the harder it becomes to troubleshoot if traffic drops.
Low risk
You keep the domain and URL structure and change few variables. With a correct redirect plan and preserved URLs, the risk of losing rankings is small.
What you should doVerify the redirects, submit a new sitemap and monitor Search Console for the first few weeks.
An indicative assessment – not a guarantee. The outcome also depends on how well redirects, the sitemap and indexing are handled.
More free toolsThe risk scale follows a simple logic:
- Low risk – you keep the domain and URL structure and change few variables. With correct redirects, the traffic loss is small.
- Moderate risk – a couple of central variables change. Manageable, but it requires a considered redirect map and follow-up.
- High risk – several heavy variables change at once. A visible traffic loss is likely and troubleshooting becomes difficult.
- Critical risk – in practice you are changing everything at once. That maximises both the risk of a loss and the time it takes to understand what went wrong.
Why do you lose rankings even though you followed the checklist?
The most common cause of lost rankings in a migration is not a single technical error – it is that too many things change at the same time. When you change platform, domain, design and content in the same launch, it becomes impossible to tell what caused a loss. If you have made big changes, Google may also simply need some time to understand your new content structure, even if you have done everything right.
The usual culprits are:
- Old URLs that return 404 instead of being 301-redirected to their new equivalent.
- Redirects that point to the wrong place, chain over several steps or go to the home page instead of the right page.
- The new website going live with a forgotten noindex setting or a blocking robots.txt.
- Content that is thinned out or rewritten so heavily that the page's relevance for the keyword disappears.
- A changed internal link structure that redistributes the page's internal link value.
If you want to dig deeper into why rankings drop, we go through the causes in detail here: Website not ranking? The 10 most common causes. If traffic fell for a reason other than the move – a manual action or a core update – the diagnosis is in Google penalty or lost rankings?.
Step by step: how to migrate without losing rankings
A controlled migration follows the same basic sequence whatever the platform. The most important work happens before you go live.
- Map every URL 1:1. Export every existing URL and pair it with its new address. This document is the backbone of the whole migration.
- Put in 301 redirects for every changed URL. A 301 tells Google the page has moved permanently. Google confirmed in 2016 that 301 redirects no longer lose PageRank – in principle, the link value is passed on in full. The older rule of thumb that 10–15 per cent leaks away is outdated. Source: Search Engine Land.
- Keep priority pages intact. Where you can, freeze URLs, titles and core content on the pages that bring in the most traffic and links. Save design changes and rewrites for after the migration.
- Check the index settings before launch. Make sure the new website is not left with noindex or a robots.txt that blocks Google. This is one of the most common and most expensive mistakes.
- Update and submit a new sitemap in Google Search Console straight after launch, so that Google finds the new addresses faster.
- Monitor indexing and traffic closely in Search Console and your analytics platform for the first 4–8 weeks. Catch 404 errors and faulty redirects while they are still easy to fix.
Should you change domain at the same time?
If you can avoid changing domain at the same time as you change platform, do. A domain change is the single biggest risk factor in a migration, because in practice Google has to relearn the whole website's authority at the new address.
If you have to change domain, there is a concrete tool: Change of Address in Search Console. It actively forwards signals and prioritises the new domain for 180 days. The redirects, however, should stay in place for longer than that – Google recommends at least a year, ideally permanently. The details are in Google Search Central.
Our recommendation: keep any domain change separate in time from the other changes. Change platform first with the domain preserved, verify that the traffic is stable, and make the domain change a separate, controlled step.
What is special about changing e-commerce platform?
An e-commerce migration is technically more demanding than migrating a regular website, because there are more URLs and more ways to lose them. Product pages, category pages and filtered URLs all need to be mapped, and discontinued products need a considered redirect strategy instead of being left as 404s.
What needs extra care when you change e-commerce platform:
- A redirect map for all product and category URLs, not just the ones with the most traffic.
- Structured data for products (price, stock status, reviews) that needs to carry over to the new platform.
- Handling of discontinued or replaced products – redirect to the closest relevant page.
- A check of how the new platform generates URLs for filters and variants, so you do not create duplicates.
For most Swedish online retailers, Shopify is the platform we recommend. Whatever the destination, the same principle applies as for other migrations: do not change everything at once, and prioritise redirects for your strongest pages for revenue and traffic.
Once the migration is done, ongoing optimisation takes over. Category structure, product copy and the technical traps specific to online shops – filter pages, pagination and duplicated product URLs – are covered in the guide to e-commerce SEO.
How long does it take for the traffic to come back?
It depends entirely on how big the change was. If you only change platform with the domain and URL structure preserved, the traffic is not affected at all. A domain change is a completely different story.
A study that analysed 892 domain migrations found that it took an average of 523 days for the new domain to reach the same organic traffic level as the old one – and that 17 per cent of the websites had not recovered even after 1,000 days. The figures relate specifically to domain changes and are based on traffic estimates from third-party tools, but they show how costly a badly handled migration can be. Source: Search Engine Journal.
The lesson is not to avoid migrating – sometimes a change is exactly the right decision. The lesson is that the scope of the change determines the timeline, and that a controlled, step-by-step migration is what protects your traffic.
What should you demand from an agency that handles the migration?
A serious migration is planned, not improvised. If you bring in help, you should be able to expect a clear plan before anything goes live.
- A complete redirect map where every old URL is paired with its new address.
- A test environment where redirects and index settings are checked before launch.
- Setup and monitoring in Google Search Console, including a new sitemap.
- A plan for follow-up in the first few weeks, with actions if the traffic dips.
- For a domain change: correct use of Change of Address and redirects that stay in place for at least a year.
What separates a successful migration from a costly one is rarely a single button – it is the combination of technical precision and an understanding of what actually drives your traffic. If you are facing a platform change and want to get that part right from the start, get in touch or read more about our services.
Common questions about migrating a website
Do you always lose rankings when you change platform?
No. The risk depends on how much you change – not on the platform change itself. If you change tools but keep the domain and URL structure, and put correct 301 redirects in place, the risk of losing rankings is small. The loss happens when several things change at once (domain, URLs, design and content) or when redirects are missing altogether.
How long does it take for Google to index the new website?
For small and medium-sized websites, most pages are usually reindexed within a few weeks; larger websites take longer. Submit a new sitemap in Google Search Console straight after launch to speed up the process. If you are also changing domain, the Change of Address tool forwards signals for 180 days.
Do you have to redirect every old URL?
Every URL that changes and has value – traffic, backlinks or internal linking – should be 301-redirected to its closest equivalent on the new website. Never send everything to the home page; it signals to Google that the old pages lack a relevant replacement. Pages with no value at all can be left out, but a 1:1 mapping is always the starting point.
How long does it take to recover if the migration has gone wrong?
It varies widely. A study of 892 domain migrations found that it took an average of 523 days to reach the previous traffic level, and that 17 per cent had not recovered even after 1,000 days, according to Search Engine Journal. The figures apply to domain changes. If only the platform has changed and the URLs are preserved, recovery is usually fast – start by checking redirects, index settings and 404 errors.
Does a platform change affect visibility in AI answers such as ChatGPT?
Yes. AI answers in ChatGPT, Perplexity and Google's AI Overviews rest on the same foundation as regular search: crawlable content, clear structure, schema markup and brand mentions. If you lose structured data or break links in the migration, you can disappear from the AI answers. So treat schema markup and any llms.txt file as migration steps, not as an afterthought.
