I have two domains: let's call them A (currently in production) and B (a test domain).

For reasons I can't disclose, I need to switch from A to B while keeping everything else the same except for the domain name.

The biggest concern is OAuth login via Google.

Currently:

• The Google OAuth consent screen has been submitted and approved with A as the application homepage.
• B is already included in the authorized domains list in this application.
• I have separate client IDs issued for A and B. (but same application)

My Plan:

1. Update the application homepage in the Google OAuth consent screen to B and go through the review process again.
2. In the OAuth settings for A's client ID, add B to the Authorized JavaScript Origins and Authorized Redirect URIs.
3. In the OAuth settings for B's client ID, add A to the Authorized JavaScript Origins and Authorized Redirect URIs.
4. Keep the client ID and secret unchanged in both the production and development servers (since I want existing users from A to continue using their accounts on B without any issues).

Concerns:

Once step 1 is completed (changing the consent screen to B and getting approval), will OAuth stop working on A?

Ideally, I want to transition seamlessly without breaking OAuth authentication on A before fully switching to B. (One or two hours is fine.)

Is my approach correct? If not, what would be the best way to handle this transition?