Planning and executing a successful site migration can be a stressful experience to say the least.  The bigger the site, the larger the risk that something can go wrong.  If your website is an e-commerce site, then the effects of a poor site migration can be catastrophic for your business.  Unfortunately poor site migrations are all to common, as a lot of businesses don’t fully understand or have the time or budget to consider SEO.

An Example of a Poor Site Migration


This search visibility graph taken from Searchmetrics shows what can go wrong when a site migration isn’t handled properly:  The search visibility of your website on Google can plummet very quickly, often mimicking the look of a Google Penalty.  A lot of the time website owner will not become aware of this until it is too late.

Assess the impact of the migration

  • Are you performing your site migration at the best time of year for your business?  For example, it is not necessarily the smartest idea to perform a site migration just before Christmas if that is your peak season.

How do I find out when is my peak season?


If you have only just started your business, and you want to find the peak season for organic searches you can use the Google Keyword Tool to find the peak seasons for your business.


You can either enter your keywords into the tool or you can enter any website.  This could be your own website or a competitor website.

  • Ideally it would be better to get the migration sorted around 2 months before your peak season so you can iron out any potential problems. It is also a good idea to make sure that the migration is scheduled in for as early as possible in the week to give you the best possible chance to make sure you have resolved any of the core problems that may arise during the week.

Take a full site crawl of the old site a few days before it goes live

Using a tool such as Screaming Frog or Botify, (Other site crawlers are available), you can easily create a copy of the old website architecture.  Mapping the old site URLs to the new site URLs is a core part of the migration process, so you need to understand the site architecture of the old site. To do this make sure you schedule a call with the developer of the website to run through the new URL structure.

Want to schedule your pre site migration crawl?

If you want to schedule a crawl you can use a tool called Punctual Frog.  This is a program that runs alongside Screaming Frog and will start a Screaming Frog crawl any time you want.  (There are of course other ways to schedule a Screaming Frog crawl, but in my opinion this is the no nonsense method).

The only issue to be aware of if you are scheduling a crawl is memory allocation.  If Screaming Frog runs out of memory half way through the crawl, then it will stop and notify you to increase the memory.  You can, however side step this by following the step-by-step instructions below on how to increase your memory allocation:

How to increase memory allocation on Screaming Frog


Step by Step (PC):


  1. pcLocate your Screaming Frog installation (C:/ Program Files Screaming Frog etc.)
  2. Find the file “ScreamingFrogSEOSpider.l4j.ini
  3. Ctrl F to Find 512.  Change 512 to 1024 and click save


Success! You have now doubled the Memory allocation for Screaming Frog.

Step by Step (Mac)


  1. Go to Terminal
  2. Type in defaults write uk.co.screamingfrog.seo.spider Memory 1g
  3. Get back to creating sick beats on Logic and updating your Tumblr Cat Photo post.


Success! You have now doubled the Memory allocation for Screaming Frog.


Check for URL changes

Often it can be said by parties involved in the migration process that “No substantial URL changes will be made”, but bear in mind that even slight changes of wording can mean the difference between a successful redirect and one that 404s. It is essential, if possible, to get a copy of the proposed site structure beforehand. Doing this will allow you to create a redirect map in the most straightforward way possible.

Download a links report for the old site

seo-reportUsing a tool such as Majestic, Ahrefs, OSE or any other link tool you have access to, download all the links that point to the current pages on your existing site.   Having this data will help you to understand the authority of the pages and can help you to prioritise which are the most important pages you need to migrate first.  Failing to redirect these pages to the new versions can result in a sudden drop in search visibility after the site migration.  Be aware of your most valuable links.  Using a tool such as Majestic, you can do this quickly and easily by filtering the links by Trust Flow.

Understand exactly which pages are indexed in Google

google-search-engineYou can use tools such as Scrapebox to understand how many pages are indexed within Google.  Or you can simply scrape the results onpage from Google using a screen scraper.  Record this data and save it to compare against the new site. It is best to conduct this analysis the day before the site migration if possible so you get the best idea of which pages are indexed in Google.

Create a 301 URLs Redirect Map

seo-redirect-mapping-excelThe URLs redirect map will outline any URL changes from your old site to your new site.  So for example, if you migrated some of the more successful standalone pages to the /news/ section on your website, you would need to have the old URL in column A in Excel and the new /news/ URL in column B. This is the clearest way for your developer to upload the redirects directly to the website. Save as a CSV and send to the developer.

Backup, Backup, Backup!

backup-siteIt should go without saying that it is a good idea to create a backup of your site before a site migration.  If you have a developer or development company, then this is something that may already be automated, but make sure you schedule in a backup to be made of the site before the migration.

Benchmarking SEO site performance

It is a good idea to check the performance of the old site in terms of site speed and any other factors.  You can use tools such as the Google Page Speed Insights Tool to get a feel for how the site performs both on mobile and desktop.



Once you have performed all of the above checks it is a good idea agree with the website owner and developers on a day for the site launch.

Check the Robots.txt file



Make sure the robots.txt file www.yoursite.com/robots.txt is how you expect it to be.  Sometimes developers will block a test site from Google using robots.txt and then forget to take off the command.

Check the <head>

check-headAgain, some developers will use the noindex meta tag to exclude certain pages or the whole site from Google.  Make sure this is removed when your new site goes live, otherwise you may wonder why you are not getting any Organic Traffic.

Check your 301 Redirects are working as planned

If you have moved any URLs to new sections of the site it is likely in your redirect map that you will have 301 redirected them to new pages.  Check that these redirects are working as expected.  It is also a good idea to try to avoid redirect chains.  These can be spotted ad hoc using Ayima’s redirect path tool, or can also be found using a tool such as Botify.

Audit your 301 Redirects in Screaming Frog

Auditing your 301s is really important to check against any things that you may not have checked, or may have missed. A quick way of auditing your redirects is simply to load them into Screaming Frog in List Mode. When you press the start button Screaming Frog will then check the links and find their current status. Any URLs that return a 404 error (or other unexpected results), should be copied back into Excel and replacement redirect URLs should take their place. If the redirect has no equivalent in the new site then it is best to redirect this into the parent category, or failing that, the homepage.

Check the XML sitemap is working as planned

xml-sitemapAgain, it is very important to check that your XML sitemap is working as you planned.  If it has changed, upload the new XML site map to Google Search Console to help index any new pages.

Ensure the website is accessible to search engine bots

When creating a site it is often common for developers to noindex, nofollow the entire site’s pages so they don’t appear in Google. It is also common practice to block the site within the Robots.txt file. When you have s

robots-checkUse Fetch as Googlebot in Google Search Console to see if the website is accessible to Googlebot.

Test for any Broken Links

links-brokenSearch for any broken internal links that go to 404 errors.  If you have completed your URL redirect mapping properly then this should not be an issue, but it is always worth checking everything has been implemented properly.


Check Google Analytics code is implemented properly

google-analytics-logoSometimes with a new site launch the Google Analytics code can be removed by mistake.  Make sure that it is still on there.  A simple search within the source code can help you to do this.  Or if you are feeling fancy, you can use a tool such as this one: http://www.gachecker.com/

Speed up indexing with Social Signals


Generally if you have a high traffic site then there should be much problem in indexing any new pages on your site.  But if you are finding that the new pages aren’t being picked up as quickly as you had hoped they would be then you can speed up Google indexing by sending social signals to the culprit pages.


Make sure your internal links are follow

This kind of goes without saying really, but again this should be one of your standard checks after you have recrawled the site.



Let websites linking to your site know that you have updated your website URL

Let any of the important websites linking to your key pages know that your URLs have changed where appropriate.  This process can sound daunting, but with the aid of outreach programs such as Buzzstream this can be a lot easier than you think.  To do this within Buzzstream you can set up a quick outreach template that can be used across all of email contacts.

Check in Google Search Console for any errors

It is very important to be on the lookout for any errors that appear in Google Search Console in the days and weeks after you have migrated your site.  Make sure you allocated time into your site migration timetable to check Search Console daily to see what the impact has been.

Compare Pre-migration benchmarking to new site post migration

This is the real crunch time for a website.  Is the new website performing as well as the old website? If it isn’t, why not?

Published by Chris

Chris is a London SEO Consultant working as an SEO Account Director for Blue 449, part of Publicis Groupe.

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