How to See Bandwidth Usage by Each App or Process on macOS

data transfermacos

I see suddenly that my downstream bandwidth is 400 KBps which is the maximum my ISP gives me, so there's an application downloading at its top capacity.
The thing is I didn't start any download, so it's doing it in the background without telling.
How can I know which app or process is using it?
Or, basically, how can I determine how much bandwidth each open process or application is using?

Best Answer

This help at all? Take a look at the NetMonitor Sidekick add on. Have not tried it myself but will probably load on virtual machine to see how it works.

http://netmonitor.s3-website-us-east-1.amazonaws.com/net.html