We are hosting customer data on behalf of companies/clients, and one of our tasks is to send out a very specific transactional email from us (with our email address as sender and reply-to) to clients customers.
We are trying to move away from storing the personal part of a customers data, including his email address. Of course, in order to be able to send out an email to a customer we need to at some point have access to the email address, but in our view it's a step in the right direction to retrieve the email address from the client during a session instead of retreiving it from our own database.
The problem now is that our unwillingness to have email addresses stored anywhere rules out using email service providers like Sendgrid. Instead we need to send out lots of emails through our own server, and this might hurt deliverability. I've been looking for a kind of "self hosted Sendgrid". One who will enable us to send bulks of emails, and one we can tweak to not store the sent emails.
One solution I've found is sendy.co who defines themselves as:
Sendy is a self hosted application that runs on your web server.
This sound promising, but then I read that emails are sent through Amazon's cloud:
Sendy uses multi-threading to send emails via Amazon SES.
I suppose this leads us back where we started, because then Amazon is storing the email addresses.
As I understand, the high deliverability that ESPs achieve is not only caused by state-of-the-art email headers, but also by their servers being recognized by Google/Gmail, Microsoft and other email hosts. So maybe a high deliverability just isn't possible without an ESP. But is there an alternative approach that lets us achieve relativly high deliverability without needing to involve a 3rd party server to do the sending?