Why migrate a website?

Any kind of website migration carries a level of risk, but if the potential benefits outweigh this, it’s inevitable at some point that most websites will need to be migrated in some way or another. It could be that your current website is no longer fit for purpose, you could be trying to amalgamate several different websites into one, or you might be considering structural changes that will significantly affect the user journey. Whilst there is plenty of crossover between different types of migration, there are some actions that you may take with one kind that you shouldn’t with another.

This guide aims to help you define the best plan of action for your specific website migration, helping make sure that you mitigate the risks involved.

Whether you’ll be actually carrying out the technical tasks yourself, or have web development support to handle that part of the process, this guide aims to cover all common bases so that it can be used by both those overseeing and those doing the hands-on migration work.

Which type of site migration are you doing?

Depending on how literally you take the term, site migration can take many different forms; including:

Migrating an existing site from an old domain to a new one e.g. www.example.co.uk to www.example.com or from www.example.com to www.bestexample.com
Migrating the site from one platform or CMS to another e.g. Shopify to Magento 2 (sometimes called replatforming)
Merging parts of an existing website with others on the same site e.g. amalgamating pages
Merging several sites into one e.g. moving from separate international sites to one global domain with subfolders e.g. example.de and example.fr to example.com/de and example.com/fr
Creating a new website on your existing domain e.g. redesigning for a rebrand
Moving an existing site from http to https e.g. http://example.com to https://example.com
Making big changes to your site navigation or URL structure/hierarchy
Adding or fundamentally changing a mobile version of your site
Moving from one server to another

To further complicate matters, the answer can be several of the above, all at once.

What can go wrong if you don’t migrate a website properly?

The list of issues that can result from a poorly implemented website migration and virtually endless, but the major concerns that most people have are related to short or long-term damage to the business caused by:

Losing traffic (organic and potentially paid)
Losing search engine visibility, trust and authority
A big drop in conversions/sales
UX problems - people not being able to find content/products
Website downtime or major bugs, resulting in lost revenue

We've made a process guide to help you make sure that you’re as prepared as you can be for the moment when the switch is flipped. Regardless of which type of site migration you’re doing, the below applies.

Site Migration Checklist

Make a plan for your site migration

Regardless of which type of site migration you’re doing, it’s vital to have a clear plan on why and how you will achieve your objectives through your activity. The scope of your migration could be anything from simply moving to https from http without any other changes made, or it could involve numerous changes to your entire web presence all at once, which requires a much more complex plan.

Depending on how many stakeholders are involved in deciding what to change with this migration, the scope of the project could vary. It’s important to assess the risks of each aspect as well as the potential benefits and ROI. This can help you to prioritise which elements you want to include with this migration and what can potentially wait until a further phase if it’s not essential now.

Your plan will not only need to include the fundamental changes you want to make to your site as you migrate, but also realistic timescales for when each thing can be done. Each task needs to be allocated to a specific person and deadlines set. There will be some tasks that are reliant on others being completed before they can be started, so it’s vital to map all of this out before you start anything else. Build in some contingency and testing time to your plan too before your official ‘live’ date.

1. Benchmark your current site

You’ll need to know how your newly migrated website is performing in a wide variety of areas and the easiest way to prepare for that is by thoroughly benchmark how your site performs before the changes. As well as the more obvious metrics, such as organic traffic, conversions/transactions and revenue, it’s also worth using Google Search Console to export the entire last 16 months of data it holds, which you can revisit in the future without having lost any of the historical information from how your old site performed in terms of search engine visibility, clicks and the search queries used for specific pages. You may also want to benchmark keyword ranking and site speed.

2. Make a copy of your existing site

It’s surprising how often people make radical changes to their website without having backed it up properly first, including any databases. Depending on how your site is built, there may be some plugins which promise to help you with this – but experience tells us that relying on plugins alone can be dangerous. Having a full and recent copy of everything will help ensure that in the worst-case scenario, you can simply roll back to your current version of the site and no data will have been lost.

3. Prepare your new site from an SEO point of view

Making preparations for your migration from an SEO point of view is vital. If the changes are minimal e.g. you’re simply moving domain or from http to https, you may not need to consider all of the below, but if you’re making bigger changes to site or URL structure, are getting rid or adding new sections etc, you’ll need to factor in things like:

Written content, headings, page titles and descriptions
Internal linking
Structured data implementation
Meta robots directives
Sitemaps (XML and HTML)
Mobile (if AMP or mobile version are being used)
Site speed/loading times
Implementing Hreflang (if international sites are being used)

4. Create a 301 redirect map

Depending on the size of your site, this can be anything from a fairly simple task to a bit of a mammoth one – but getting it right can make a big difference to the success of your migration, both in the short and medium term. Crawl the old website to ensure you have a copy of all your indexable URLs and use a spreadsheet to make sure that you have a plan about where every single one of them will be redirected to for the new site. If you have thousands of URLs to work through, you will want to identify the most important pages to prioritise your task. You can use Analytics data to see which pages get the most organic traffic or pageviews, are responsible for the most conversions or revenue in the last year and which have the most external links pointing to them.

Redirecting high performing pages to an equivalent page on your new site is essential if you want to avoid lost potential traffic, revenue, conversions and bounces. If the exact content isn’t going to appear on your new site version, make sure you redirect to as close a relevant match as possible. Many people use a short cut and redirect many pages to the homepage rather than finding the next best alternative. This can definitely have a detrimental impact on user experience and potentially send negative signals about your site to search engines too. If you’re running any paid media activity, such as PPC ads or catalogue ads on social media, the URLs and feeds involved in this will also need to be updated with any changes.

Once you set the redirects live, recrawl the site to check for any missed URLs showing 404 errors or any redirect loops. Check that your image or other media file URLs have also been redirected where needed. This is especially important where images are responsible for bringing in organic traffic or have been linked to by other sites.

5. Update links

Updating your internal links is an important task once the new site or other migration changes are live. Internal redirects can make pages load more slowly and could have an impact on how search engine bots can crawl your site.

You should also set a task for contacting every good quality and authoritative external site that links to yours and ask them to update the linking URL. This can be a little hit and miss, but the chances are that at least some of the links will be updated.

7. Live day checks

Some checks that you can perform as soon as the site is live include:

Checking that search engines can now crawl the site i.e. are not blocked by the robots.txt
Checking that redirects are behaving as expected by visiting a wide range of old URLs
Checking canonical tags
Checking server responses for important pages
Checking that XML sitemap(s) have been uploaded to GSC
If your domain has changed, checking that the ‘change of address’ tool in GSC has been utilised
Checking that any disavow file you have uploaded is up to date

8. Post-migration review

Some potential problems with a migration can be an instant spot e.g. if an old page hasn’t been redirected and now displays a 404. However, some things may only become apparent after a few days have passed. You should:

Keep a close eye on crawl data in GSC – there should be a spike in activity after the launch as the bot finds ‘new’ pages to crawl. If there isn’t a spike – this could mean something is stopping the bot from doing its thing.
Check for crawl errors in GSC on a daily basis at first. This will highlight any missed redirects for important pages.
Start to check against your original benchmarks e.g. site speed, traffic, GSC impressions and clicks, transactions or conversions etc, but don’t panic if things take a while to get to expected levels
Check that the site is performing as expected across both desktop and mobile.

If your website is large, it can take months before you are able to accurately judge whether the migration has been successful. For most sites, 1-2 months should be enough time for you to properly assess the performance of the site now against how it used to perform and your latest KPIs.

If your user journey has radically changed, it can be a while before conversion rates improve as people need to get used to a site that works very differently for them from how it used to. Don’t make any UX or CRO changes based on early data – wait until things have settled first.

Engagement metrics over time can help to show you whether your users are finding the new version of the site better for their needs. Look for bounce rate changes, average time on page etc. Also split down your conversions or transactions by types of page (e.g. category or product) and device. This will help to flag where things might be falling down if the figures aren’t as positive as you were expecting.

9. Document the experience

Documenting the process of migration, from your initial plans, through to implementation records like redirect maps, and a report into the success of the migration, will all help to give you a rounded view of the process and which parts worked well, along with improvements that could be made if you tackle something like this again in the future. If something does go wrong, this documentation could also be a big help in pinning down where and when the issue happened, meaning you can get things fixed sooner and minimise any negative impact on your business.

We hope that you’ve found this guide useful. Good luck with your website migration!