Pretty cool. Does the tool process bounces, complaints, and unsubscribes, e.g. auto removes from future mailings? Have you considered using a hosted platform that uses Amazon SES rather then hosting Sendy or other tools yourself? I own BigMailer and our clients with established SES accounts (high daily rate limits > high limit per sec) see 1m emails go out in a little over 1 hour. I always wonder why people choose to…
listmonk does have unsubscription and blacklisting, although not bounce processing (yet. todo.) listmonk is a replacement for Sendy. You can connect your SES account to it using the SES SMTP interface. Integration with in-house DBs was a top reason for us.
Try to implement bounce processing soon - an average list decays at 2% per month (3% for B2B lists) so in a few months, the bounce rate can be high enough for mail box providers to start blocking your emails due to attempts to send to large number of invalid email addresses. Especially sensitive issue with your list size and sending volume.
There might be a couple more useful nuggets in this article on email deliverability best practices https://www.bigmailer.io/blog/improve-email-deliverability-b...