The Content API for Shopping easy onboarding authentication method and tab, which create a service account for you, will not be available in Merchant Center Next . Easy onboarding is still available in Merchant Center Classic.
You can still use existing service accounts that you created using Merchant Center Classic. To set up a service account without using easy onboarding in Merchant Center Classic, follow these steps:
Ensure you have an existing cloud project or create a new one in the Google Cloud Console .
Generate or access your service account credentials.
Download the JSON private key from Google API Console. This JSON private key can be used in the same way as the one downloaded from Merchant Center previously.
Add the new service account as a user to your Merchant Center account. If you’re a third-party developer (and don’t have access to the Merchant Center UI for the account), your client will need to complete this step for you.
For more details, see the API documentation .
If you have any questions or concerns, please don't hesitate to contact us via the forum .
Benji Rothman, Content API for Shopping Team