Gmail API supports a UserID param but how do I setup a Google account with access to multiple mailboxes?

Question

I have an application which needs access to mailboxes for an organization but likely only needs access to the mailboxes for the sales teams and not the mailboxes for the rest of the organization.

For Office 365 we create a service account and get it delegated access to each of the mailboxes it needs to read emails from.

It seems like the Gmail API supports a "userID" parameter.

How can I configure a service account user thru the Admin portal to have access to multiple mailboxes?

Answer 1

Unfortunately this is not possible because a service account acts on behalf of a user who runs the script and does not have the authorization to access other mailboxes.

As a workaround, in the Admin console, the administrator of the domain is able to set up the routing settings for Gmail in a such a way that a copy of all emails addressed to the Sales Team (Organization Unit “Sales Team”) will be delivered to an additional recipient - who will run the API.

When you set-up the routing settings as explained here and add a recipient to whom to deliver a copy of the messages, you can use the option “Advanced”, which allows you to decide to for example to forward attachments or Spam messages as you can see in the image below.

Furthermore, if you don’t want to forward all messages, you can set-up content compliance rules for the inbox of the additional recipient to whom a copy of the messages will be delivered.