Triggering an newsletter via api externally

Problem/Motivation

Hi and thanks for the long years of work on this project!!

I cannot find an answer in the Issues for this situation:

I would like to be able to send into Drupal some data, and have it sent out to the Newsletter at that moment.

Which api should I look into for this? Would it be like Node Import, and then once it imports, I could set it to trigger the Newsletter email?

Thanks very much for all these great features!! :D