New stores show 2 .myshopify.com domains (Primary + Redirect) and OAuth redirects to the “redirect” domain — expected?

Authentication & Access
1

Hi everyone — I’m a developer of a public app in the Shopify App Store.

Recently, when creating new Shopify stores, I’m consistently seeing two .myshopify.com domains listed under Settings > Domains in the Shopify admin:

  • A branded/expected .myshopify.com domain (appears to be the Primary domain)
  • A second .myshopify.com domain that looks non-branded / less readable (appears to be a Redirect domain)

From Shopify’s domain documentation, I understand that Shopify supports Primary, Alias, and Redirect domains, and that changing the .myshopify.com domain can result in the previous one becoming a redirect.

Problem: Our OAuth/install flow historically keyed store identity using the primary .myshopify.com domain. For older stores, the “shop domain we receive/are redirected through” always matched the primary. But on these newer stores, the flow is now redirecting/returning using the second (redirect) .myshopify.com domain, which doesn’t contain the expected shop name. As a result, we don’t recognize the store and can’t complete authorization cleanly.

Questions:

  1. Is it expected that new stores have two .myshopify.com domains (one primary and one redirect) by default, even if the merchant hasnt manually changed domains?
  2. Is it expected that Shopify might redirect/return OAuth through a redirect domain rather than the primary domain?
  3. What is the recommended approach for apps to reliably identify the store when multiple .myshopify.com domains can exist (primary vs redirect)?

Extra context: This is happening across multiple newly-created test stores (including stores on trial), while older stores created earlier didn’t show the same behavior, but the older stores that i have checked are not on free trial.

Thanks!