I am actually wondering if there is any way, as an iphone/android app developer, to guarantee the request comes from the device (and not from a curl req, e.g).

I am actually wondering if there is any way, as an iphone/android app developer, to guarantee the request comes from the device (and not from a curl req, e.g). Of course virtually any method (auth token, ...) can be broken, but there must be a way to make it difficult enough. Any advice from app developers on how to do this?