Why can SEO suffer after a website migration?

Friday, July 14, 2023

Websites will undergo migrations for many reasons. Sometimes this is for aesthetic purposes, improving their tech stack or legal requirements. However, no matter the reason, SEO needs to be included from the very beginning of any website migration, as there are a number of common pitfalls that can dramatically affect organic performance post migration.


Written by

SEO Manager

Not all migrations have to be difficult though, and some can bring extremely positive results. Here are some of the most common SEO issues during your migration that could be dragging down your website’s performance:

Common SEO migration issues

Lack of correct redirects

During website migrations, URL structures may change. This is especially true ecommerce websites that may have common subfolders for products and/or categories.

When this happens, it is imperative that you set up redirects from your old page to the new page - using a 301 redirect if this is a permanent change. Failure to do so can result in the strength of old pages being wasted, as these pages will have historic value that search engines recognise - whilst new pages are just that, new; with no historic value attached to them.

Furthermore, migrations are often combined with a content audit, in which websites will remove irrelevant, or outdated content. When this happens, these pages also need to be redirected to a similar page. Whilst this may seem like a good time to do a content audit, we would recommend against doing so in a migration. The reason for this is that this then adds further complexity to the migration process, which can make it much more difficult to diagnose any issues.

Changes in tech stack

When migrating to a new tech stack, there may be wide scale changes happening under the hood of the website - this includes changes in rendering options, JavaScript files and much more.

Some CMS may come with more bloat - this can often come in the form of plugins that aren’t needed. One example could be if you had a website on Wordpress that was primarily a blog and lead capture, having e-commerce functionality with WooCommerce would be a waste of resources.

This can cause websites to load slower, be harder for search engines to render and understand, ultimately impacting organic search rankings and even other channels such as paid search.

Disallow rules that are ported over from staging sites

It is best practice that staging sites are used to build the site and test functionality. From an SEO perspective, we will often recommend a rule in the robots.txt file: Disallow: /.

This tells search engines to not crawl or index the staging site. We need to do this otherwise the staging site can be found within the search results and potentially compete with the live website for organic rankings.

Occasionally, we will see that the Disallow: / rule has been ported over from the staging site onto the live site when released. If left unchecked, a site can fall out of the index completely - imagine not being able to find your website on Google at all, even if you search for something only your site offers.

This can obviously be devastating for websites, as organic traffic and leads/revenue will plummet, eventually to nothing.

How can I avoid these issues?

#1: Include SEO from the beginning

Even before signing off the migration, it would be beneficial to include an SEO at the very beginning. This is the most important step that you can take - as any SEO professional worth their salt will be able to guide and help you through a migration.

If the SEO has been working on the site for a while, they will understand where the potential pitfalls could be, and what opportunities can be capitalised on to improve the long-term performance of the site.

The earlier that you can involve an SEO professional in a website migration, the better!

#2: Fully understand the reason and the scope of the website migration

The first question you should be asking yourself is “why do we want to migrate the website in the first place?” - this will allow you to start thinking about what the potential changes will be. 

Even if they are purely aesthetic, SEO should be considered. For example, search engines will treat content in accordions different to always visible content. So if you are introducing accordions to the website, there needs to be a plan of action to ensure they work for your SEO as well as UX.

#3: Audit the website before and after the migration

It is important to take stock of your current website before migrating over. What this allows is for you to find technical errors that could be fixed with the migration, or should be included in the migration brief. This can also cover any CMS inclusions, to help you overcome blockers.

This audit acts as a snapshot in time. This should include URLs that can be crawled and found within your analytics platform.

Once the migration has been completed, it is important to audit the new website as soon as possible. These findings can be compared against the pre-migration audit to identify any issues or any pages that may have been missed.

Migration expectations

Website migrations are a big deal. They often impact all pages on the website, whether that is in just design or functionality. This is why it is important to have an SEO professional to guide you through the process and fix any issues that will arise.

There will always be some issues with migrations. It may be that the new CMS doesn’t have an out of the box solution for something that you may need in the future, or pages could have been missed by developers. Thorough pre and post migration audits should cover most issues and safeguard your organic rankings as well as possible.

However, with any wide scale changes to a website, there will be fluctuations in search. This is just search engines understanding the new setup of your website. Fluctuations can last a few weeks, and eventually, your new website will settle into their new organic rankings; for better or worse.

If your migration has a negative impact on your SEO, performance can be recovered! If you’ve had a website migration that has suffered a drop in traffic, leads or revenue, then get in touch with one of the SEO team.