The structure for this already exists somewhat in the Chat Integration and OneSignal plugins.
I think if I were going to build this, I would build a generic notifier plugin along the lines of the Chat Integration plugin that could support multiple APIs. That way you could use any SMS integration service, as well as use it for similar use cases, like replacing OneSignal for the RN whitelabel app.
@pmusaraj There’s a potential cross-over here 