If you are just doing polling when your app is in the foreground, you should not have to write any native code. All of the polling can be handled in your action

If you are just doing polling when your app is in the foreground, you should not have to write any native code. All of the polling can be handled in your actions. If you need to poll in the background when the phones screen is locked, then you will need to write native code. Writing native code to do this isn't that hard (react native docs are good), it's just annoying that you will have duplicate business logic for Android/iOS.