The product adheres to Google's Bulk Senders Guidelines, which means we adopt best practices and play by the rules laid out by ISPs. We have had our product independently assessed and validated by email delivery experts, who have confirmed we have a high level of inbox delivery. However, no one can guarantee 100% delivery of any email sent, regardless of what system is used. 

We monitor email responsiveness and provide information back to the user regarding email rejections like bounces. To help with email deliverability we do ask that customers whitelist the domains included in our terms of service agreement.