[deepsun]

Well, unless it's the app that makes the call.

But AFAIK both Android and iOS disabled all call apps except for their own.

Previously they allowed as long as the keypad looked "distinctively different from the default call app", but turned that off some time ago. I can see the security reasoning, but still think there were ways to make it possible and secure.

A similar question, for example, is how to record a call, default or not. AFAIK there's no way.

[shawnz]

Android supports third party dialer apps and the article notes that this is one way you can overcome the problem (but they didn't want to take that route because entirely replacing the dialer is out of scope for their app)