I agree with this but I would put it somewhat differently. To me, notifications are a separate service, and whatever options there are for notification should be orthogonal to whatever is doing the notifying. If company A's policy is that notifications only go by email, nothing else, while company B has email, slack, and irc, that's for their respective notification services to worry about, not for each individual application that is using the notification service. To the application, it should be send_notification(content, recipient) and that's it.