How to send email to users who didnt open my broadcasts?

Hi! Happy to help.  My name is Mike and I’m the Deliverability Services Manager here on our team at Customer.io.

This functionality is actually not available within Customer.io.  The primary reason for this is that sending the same message to a recipient who you’ve already attempted to send it to is a big red flag for inbox providers and will likely result in the subsequent broadcast being sent directly into the spam folder or worse, a user generated spam complaint.  Re-sending any email to a recipient who did not open your initial attempt is something that should always be avoided.

In order to maintain the highest sender reputation possible and avoid reputation damage, inbox providers prefer if senders actually limit their sending audiences by not sending email to recipients who are not engaging.  

To that end, I would strongly recommend reviewing and applying all of our Email Deliverability Best Practices, which were constructed based on our own experience and, the guidance of inbox providers.  The best place to start would be to apply all of our suggested List Health best practices, which will allow you to focus on the users who want to receive your email the most.