What would you recommend an Android app for a gate like HTTP to SMS?

Question

Android

The task is to send notifications to users (not spam). I know about operator restrictions and other nuances.
What would you recommend a program for Android, which would:
1. Possess reliability and stability.
2. Could accept requests via http.
3. Could itself interrogate the server on http.
4. Could receive SMS and send them to the server via http.
You don't need to google for me, I can do it myself :-) But the real experience of using it and the reviews are very interesting.