I am working on an application, our process is that when a new user signs up, s/he is added to list(contact list of email service provider) with tags like 'New', 'Trial User' etc, to easily identify user status and send them emails accordingly. These emails will be transactional emails. We also send some push notifications based on these tags.
What I have tried:
I tried MailChimp but when user is added via API, it automatically sends confirmation email to contact and contact does not appear in list until contact does not confirm subscription while it is available if we access it via API.
I hope you understood my scenario, now my question is that is there any email service provider that do not send confirmation/verification email to contact(email address added via API) and the contact appears in list.