Not entirely sure what you're referring to, but if you're referring to sending transactional emails, the software engineer worries more about template_id, name, email and whatever other variables need to be passed to the email/text system - the guy in charge of "messaging" should not be the same engineer.
Aside, I hate it when we call something a "UI" or a person a "user". That's a sign that the programmatic language broke through (where it should not have) and people use it laymen terms. Calling someone a "user" in a magazine article bugs the fucking shit out of me.