One of the most critical steps to address when migrating ecommerce websites is forwarding the old site’s URLs to the most applicable pages on the new platform. This is done by updating the 301 redirects file, which tells Google and other search engines the URL and content of a specific page have permanently moved and where the information can be found on your new site. If a customer types an old URL into the address bar, clicks an old bookmark or link, a 301 redirect will ensure the same content is displayed to them post migration. 301 redirects also pass the SEO value on to redirected pages.
The most important pages to 301 redirect are the products and categories with the most search engine traffic, top selling products and the most linked content in Google Webmaster Tools. You can update the 301 file while building the new site and once you go live they will begin to redirect traffic immediately to the right pages. Carefully map the old pages to the new categories so you don’t confuse customers or Google.
Resource: Volusion's Guide to 301 Redirect
All inbound links within your control should be edited to the new site URLs. An example may be to update a product review link on your blog. A site’s linking profile is important to search algorithms and direct links are preferred over redirects.
It’s not always possible to redirect every URL to a new destination, so make sure to implement a custom 404 error page on the new site. Custom error pages look a lot better than the generic error page plus they are displayed within your store’s template, allowing the customer to use your navigation menu to find what they are looking for.
Your Checklist #2:
AppendixPart 1 - Migrate Content to New Ecommerce Site
Part 4 – Taking Your New Ecommerce Site Live