[jbardnz]

I have the exact same use case and have not been able to find a service that does it. We have a machine learning service that generates some content for each user but the rest of the email is just a standard newsletter.

In the end we just fire it from our web application like a transaction email, this has a few disadvantages though:

- Sending to our list of 100k users takes a good portion of the day, although this could be fixed if we used the bulk send APIs our transnational email provider has.

- Our marketing team can't easily edit the rest of the content in the newsletter so it generally remains pretty static or needs developer time just to send a newsletter.

I'm not really sure how such a service would work though, would the email provider make a webhook call back to your servers with the user id and you server return the content for that section?