Website migration is one of those projects that can quickly change the trajectory of an eCommerce business. Done well, it is a chance to rebuild on stronger foundations: faster load times, a cleaner site structure, better customer experience and rankings that actually reflect the work you have put in. Most brands come out the other side in a better position than when they started, and with the right preparation, yours will too.
So what actually is website migration, why does it happen, and how do you get through one without losing your mind (or your traffic)? Let us walk you through it.
Table of Contents
- What is Website Migration?
- Why Do Businesses Migrate Their Websites?
- How Does Website Migration Affect SEO?
- The Website Migration Process: A Step-by-Step Overview
- How Long Does a Website Migration Take?
- eCommerce Platform Migrations: What You Need to Know
- Should You Hire an Agency for a Website Migration?
What is Website Migration?
A website migration is classed as any significant structural, technical or content change to a site that has the potential to affect how search engines crawl, index and rank it. Google broadly defines it as a site move, but the reality is that migration covers a much wider range of changes than simply switching platforms or domains. This includes anything that meaningfully alters the way your site is built, addressed or organised counts.
In practice, that can mean quite a few different things.
| Migration Type | What It Involves |
|---|---|
| Platform migration | Moving from one CMS or eCommerce platform to another (e.g. Magento to Shopify) |
| Domain migration | Changing your website’s URL or domain name |
| HTTP to HTTPS | Moving to a secure protocol |
| Structural migration | Changing URL structure, site architecture or navigation |
| Design/UX migration | A full redesign that alters page templates and content layout |
| Content migration | Moving, merging or consolidating large amounts of content |
Platform migration
Domain migration
HTTP to HTTPS
Structural migration
Design/UX migration
Content migration
Often, migrations involve several of these at once, which is where things get a little bit more complex. A brand relaunch, for instance, might mean a new domain, a new platform, a new URL structure and a new design all happening at the same time. That is a lot of moving parts, and each one carries its own SEO considerations.
How Does Website Migration Affect SEO?
This is the part that keeps SEO teams up at night. Search engines (Google in particular) have indexed your existing pages, assigned them authority and ranked them for specific queries. When you migrate, you’re essentially asking Google to understand a whole new version of your site. If that handover is not handled carefully, rankings can drop, traffic can fall and revenue takes a hit.
Research from Ahrefs found that even well-intentioned migrations regularly cause significant drops in organic visibility, with recovery timelines stretching to six months or beyond when technical fundamentals are missed. Think of it like moving house. You want everyone who knows your old address to be redirected to the new one without any confusion. The postal equivalent in SEO terms is a 301 redirect, which is a permanent redirect that tells Google and users that a page has moved. Get this wrong and it is a bit like forgetting to update your address and wondering why your post keeps disappearing.
It is also worth knowing that Google does not reindex your entire site the moment you go live. For smaller sites, reindexing can happen within days of submitting an updated sitemap. For larger eCommerce stores with thousands of product pages, it can take several weeks. Submitting your new sitemap immediately after launch and resolving crawl errors quickly will speed that process up.
Common SEO Risks During a Website Migration
Understanding the risks is half the battle. Here are the most common issues that cause post-migration headaches, and why they matter.
- 301 redirect chains and loops. If redirects are set up incorrectly or in a chain of multiple hops, they slow down crawling and dilute link equity. Every hop costs you something.
- Lost or broken internal links. A new URL structure without updated internal linking means orphaned pages, which are pages that exist but cannot be easily found or crawled.
- Missing or duplicated meta data. Page titles, meta descriptions and heading tags need to carry over correctly. Losing them means losing the signals you have built up over time.
- Crawl budget waste. On large eCommerce sites with thousands of product pages, wasting crawl budget on old or dead URLs is a real problem. A solid XML sitemap and a well-configured robots.txt file are things you simply cannot skip.
- Slow page speed post-launch. A new platform does not automatically mean a faster site. Google’s own guidance on site moves reinforces this; technical preparation before launch is where migrations are won or lost.
Rankings will also fluctuate in the weeks following launch, and that is entirely normal. What you are watching for is any sustained, significant drop in traffic or visibility for key pages, not short-term wobbles that settle on their own.
The Website Migration Process: A Step-by-Step Overview
A well-managed migration follows a clear sequence, and skipping steps is where things go wrong. Here is a general framework, though the specifics will always depend on the scale and type of migration you’re undertaking.
1. Pre-Migration Audit and Data Collection
Before you change a single thing, document everything. Crawl your existing site using a tool like Screaming Frog, pull your traffic and ranking data from Google Search Console and Google Analytics, and note your top-performing pages. These are your baseline reference points, and you’ll need them to measure the impact of the migration accurately.
Specifically, make sure you capture all existing URLs alongside their current traffic and ranking data, your inbound backlink profile, page speed scores via Google PageSpeed Insights, your existing XML sitemaps and robots.txt configuration, and the meta titles, descriptions and heading tags for all key pages. Getting this right at the start takes time, but it pays for itself later when you need to diagnose any post-launch dips.
2. How to Plan Your URL Structure Before a Website Migration
If your URL structure is changing (which it often is during a platform migration), map out the old URLs against the new ones before anything goes live. Every URL that changes needs a 301 redirect. No exceptions.
For large sites, this can mean a spreadsheet with thousands of rows. Not glamorous work, but it is the difference between a smooth migration and a traffic cliff. If you’re wondering whether rankings drop after a migration, the answer is yes, some short-term fluctuation is normal. A well-planned migration with correct redirects and close monitoring will typically see things stabilise within a few months.
3. Building and Testing Your New Site Before Migration Goes Live
Never migrate directly to a live site. Build the new version in a staging environment first and test it thoroughly. Only push changes live when you’re confident everything is working correctly: redirects, page speed, mobile usability, structured data and internal linking all need checking before launch day.
4. Launching Your Website Migration: What to Do on Day One
Once you push the new site live, speed matters. Submit your new XML sitemap to Google Search Console immediately. Update your robots.txt file to make sure the new site is crawlable. Monitor for crawl errors and 404s from day one, because the earlier you catch problems, the easier they are to fix.
5. Post-Migration Monitoring: Tracking SEO Performance After Launch
The migration does not end at launch. The first four to eight weeks after going live are the most critical monitoring period. Check weekly at minimum: organic traffic versus your pre-migration baseline, crawl errors and 404 pages in Google Search Console, and ranking positions for priority keywords alongside your Core Web Vitals scores. Staying close to the data in this window is what separates a well-managed migration from one that causes lasting damage.
How Long Does a Website Migration Take?
A simple HTTP to HTTPS migration on a small site might be completed and settled within a few weeks. However, a full platform migration for a large eCommerce brand (moving tens of thousands of product pages from Magento to Shopify, for example) can take six to twelve months when you factor in planning, build, testing, launch and the post-migration monitoring period.
The recovery period for organic rankings is also variable. For a well-executed migration, most of the fluctuation tends to settle within three to four months. For a poorly executed one, recovery can take considerably longer, if it happens at all.
eCommerce Platform Migrations: What You Need to Know
Platform migrations are among the most common types of migration for growing eCommerce brands. Moving from WooCommerce to Shopify, or from an ageing custom build to BigCommerce, can make a real difference to site speed, manageability and conversion rates. But platform migrations carry specific SEO risks worth calling out separately.
How URL Structure Changes Impact Your Website Migration
Different platforms handle URL structures differently. Shopify, for instance, uses fixed URL structures for product pages (e.g. /products/product-name). If you are moving from a platform with a different structure, every product URL will change, meaning potentially thousands of redirects to map and implement. This is one of the most common sources of post-migration traffic loss, but equally one of the most avoidable with the right preparation.
Managing Pagination and Faceted Navigation During a Site Migration
eCommerce sites generate enormous numbers of URLs through filters and pagination. How your new platform handles these needs careful thought. Without proper canonical tags or parameter handling, you can end up with thousands of duplicate or near-duplicate pages competing with each other in search. This is a problem that is far easier to prevent than to fix after the fact.
Rebuilding Product and Category Page Templates After Migration
Template changes affect how your content is rendered and structured. Heading hierarchies, schema markup (particularly Product schema), breadcrumb navigation and internal linking patterns all need to be rebuilt carefully. You need to approach each element deliberately, not just assume it carries across automatically from your old platform.
Should You Hire an Agency for a Website Migration?
The short answer is yes. Website migration touches almost every part of your site’s SEO, and getting anything wrong can set you back months. An experienced agency brings the technical knowledge to get it right the first time round, as well as the monitoring rigour to respond quickly if something does not land as expected.
An agency that has handled migrations for eCommerce brands at scale will know where the risks are, what to prioritise and how to monitor recovery effectively. They will also have done this enough times to spot the problems that are easy to miss when you are doing it for the first time.
At eComOne, we work with eCommerce brands turning over £3M and above. We treat migrations with the same rigour we bring to every part of a brand’s eCommerce SEO strategy. If you’re planning a migration and want a team who has been through it enough times to know exactly where the landmines are, get in touch with eComOne and let us talk through what a smart migration looks like for your brand.
About the Author
Kieran Wright
Head of Technical
Kieran Wright has been working in eCommerce and SEO since 2014, beginning his career on the client side as a content writer before transitioning into technical SEO. He joined eComOne in 2022 and has since become a recognised voice in the industry, having spoken at BrightonSEO, eCommerce Expo London, and internationally at eCom Expo EU. […]
