How to prevent specific apps from using mobile data? So there are some mobile apps that love to use lots of mobile data, and sometimes use it when the wifi signal isn't good (e.g. Spotify). Which then leads to a nasty surprising spike in data usage during those times.

My phone is rooted, btw.
Android itself does not provide such a tool,
but you can use firewalls that require root,




If your device is not rooted, so no problem, there are some applications that use some trick that can prevent apps from being connected to internet, such as NoRoot Firewall.



  The Trick of NoRoot Firewall is that it opens a Fake VPN connection
  for making the phone to send all the packets to the Application then you
  can define for the application which one to allow and which one to
  deny.
  So it does not require root access.





If your device is rooted you can use Droid Wall  and it will do what you want.




you can download it from Google Play Store.

Note:I'm using NoRoot Firewall on My Xperia S and Xperia Z1 for a long time, even my Xperia S is rooted but i still use this application for blocking apps from being accessed to Internet.