Congratulations on working towards improving your website! This article provides info on the main things you need to do to help ensure you maintain the equity and domain authority you have built on your site for when you perform site maintenance, or with any type of site migration mentioned in the next paragraph. There are more comprehensive guides to site migrations linked at the end of this article, but this article focuses on the top things you need to do before, during and after any site migration to be successful.

A “site migration” is a term used loosely by SEO professionals for anytime a website is updated in areas that can affect their visibility in search engines. The most common migrations are domain name changes, moving or combining parts of your website, upgrading from HTTP to HTTPS, or updating platforms.

Pre-Migration Preparation

“Migration preparation” has a nice rhyming ring to it and is a top factor in ensuring success. No migration should be rushed, but site migrations range in scope. If we’re talking about a complete site overhaul, we suggest at least a month from when you tell your SEO team or agency about the migration before the launch date, or more if you have a really large, complex site. You will want to still bake in at least two weeks or more along with a few SEO meetings with your team if you are just updating the CMS or moving your site from HTTP to HTTPS. Speaking of meetings, a site migration is a big deal so the first step needs to be a meeting with all stakeholders that will be impacted by the migration and explanation of how big a project it will be, slight drop in traffic that can be expected after, etc.

One of the most important factors for a successful site migration is “redirect mapping,” or documenting where all the old URLs are going to redirect to after the launch and implementing these on a test version of the site before pushing it live. The SEO best practice is to use 301 redirects, since this status code transfers equity gained from the old pages whereas 302 redirects are designed as “temporary” redirects, usually used for ecommerce inventory that fluctuates in availability.

To illustrate the importance of redirect maps for SEO, we will give an example URL from a hypothetical client who implemented 301 redirects to the homepage for all URLs across the site and later saw a drop in rankings:

Let’s say the following URL in the example below ranked for keywords related to the “car loans” topic:

Search engines would have seen that page as highly relevant to “car loans” and related content, which is why it would have earned a high result in the search engines for related terms over time prior to the migration. Redirecting this page to the homepage would cause a drop in rank for related terms on URLs like this across the site, because the homepage is more general and not focused strictly on car loans or other specific topics each unique URL covered.

Web pages earn authority over time, which factors into ranking – and we can transfer that authority to similar web pages covering the same specific topic with one-to-one redirects from the old web page to a similar specific web page. If this URL redirected to the new car loans page with a 301 redirect, we would more likely retain the equity and rankings of the old page. In this case, we would redirect to the new folder structure of the old URL or a very similar page (Note: if no similar page exists you can redirect those pages to the homepage or kill the page with a 404 status code):

Benchmark reporting is also important to do prior to a site migration, to compare before and after traffic, keyword rankings, error reports from Google Search Console, number of indexed pages in search engines, internal and external linking metrics, and more.

You want to make sure to retain the domain authority from the internal and external links across your site. Prior to a migration, be sure to update all the links in the header, footer, and other important links across the site on the test site. Another important element that sometimes gets overlooked is updating the paid links to the new URLs. We need to show love to our paid advertising friends. Let them know when the migration is taking place so they can pull advertising during that time and ensure they update the paid URLs for after the migration to ensure a smooth transition! Other items to consider before a migration are compiling a list of schema markup that needs to be updated post migration, mobile considerations such as updating the “vary” header if needed, and that tags are consistent across mobe and desktop.

Checklist for Day of Migration and Following 48 Hours

It’s go time! Parachutes on, secure your seatbelts and let’s jump out and do this thing! The name of the game during the day of the migration is search index control and monitoring, checking redirects, and checking pages of the site and then it is audit time.

During the migration you want to make sure to ensure the site returns a 503 HTTPS status code while the site is under maintenance and a “Retry-After” HTTP header during the migration to let search engines know that the server is down and what time they should come back to crawl the site. After they are pushed live, it is important to spot check as many of the redirects against the redirect map you created in a spreadsheet against the site as possible. You will want to add and verify the new version of the site in Google Search Console and Bing Webmaster Tools for domain name or HTTPS migrations. Now that the “submit to index” tool in Google Search Console is back, we suggest submitting at least the most important pages as soon as possible to help them get indexed swiftly.

After all the initial checks during the migration, it’s time to roll up your sleeves and do a deeper audit of the site. Review for any critical SEO issues, ensure rendering is proper on mobile, ensure SEO and analytics tags are correct, analyze GSC and correct any site errors (soft 404s, broken links, etc.), and review redirect and crawl error logs.

If the site has moved from HTTP to HTTPS, you will need to make sure you’ve obtained a valid TLS security certificate and test the security certificates on all browsers. Other HTTPS elements to audit is that all page resources are updated to secure URLs and all third-party assets and external plugins are updated to the HTTPS versions. Finally, you need to confirm that all links on the page will go directly to HTTPS pages, and visitors do not redirect through an insecure HTTP page when requesting HTTP/HTTPS from old site or HTTP from new site.

When done correctly, site migrations are nothing to fear and usually cause no more than a month or so of minor disruptions in rankings and traffic. The key disclaimer with that last sentence is “when done correctly.” This was an overview of what doing a site migration correctly entails, but below are some more resources for performing a successful site migration.

Deeper Dive Resources for Site Migrations:

Moz Website Migration Guide

Site Migration SEO Checklist by Search Engine Land