Let’s say I am a MVNO (i.e. a VOIP carrier) and as such I provide customers with a DID (phone number) and a SIP service they can configure their phone to send and receive calls with. I also want to provide SMS service for their DID. Obviously I can supply them with an “SMS-like” app that connects to an API on my servers to pass SMS messages back and forth.

But what if I want my users to have a native SMS service, such that they can use whichever SMS app they want, whether that is Android Messages, or the SMS connector in Facebook Messenger, etc.

Can I write an app or connector, etc. that can inject messages into (and receive messages from) the Android SMS service so that native SMS apps would then receive them, and of course my app would need to be able to register to receive the SMS messages from said SMS apps to be sent via the API on our servers.