Is there a way to bulk test multple domains and mailboxes?

An Inbox Insight test requires sending a message from one email address to the GlockApps seed list in order to get a deliverability report. To bulk test deliverability from multiple email addresses, you can consider these options:

1) Smart tests. You can bulk import the SMTP settings for your email accounts in Sending Accounts, generate proxy email addresses for the sending accounts and send a message to all the proxy email addresses at a time. The tool will create tests in Smart Tests and the messages will be re-sent to the seed list from each email address used in the sending accounts.

2) Automatic tests. You can configure the automatic tests for each sending account and they will be trigged by our tool on a regular basis without any action from your side.

3) API (available in custom subscriptions). You can create tests and get reports via our API. This is also a great way to automate the testing process.

You can refer to these tutorials for more details:

How to use smart tests
How to set up automatic tests
How to use API

If you are not able to set up sending accounts because of the restrictions of your email service provider (if the ESP doesn’t share the SMTP settings to be used in other tools), the only option is to use manual tests. But this way, it is not possible to bulk test deliverability from multiple domains or mailboxes.