SendinBlue provides you with two extremely useful tools for testing your campaign's deliverability
Test List: Add contacts to your Test List and send them a Test Email before scheduling your campaign to deliver to all of your contacts. In addition to decision-makers, we recommend adding email addresses from various email services (@gmail, @hotmail, etc.) to this list to confirm their receipt.
Inbox Test: While drafting your email campaign, SendinBlue allows you to perform a deliverability test to major email service providers with a single click. This will also allow you to quickly find out if there are any deliverability risks with certain services.