Vobi is a mobile application which allows users to make and receive calls from their mobile phones using the Vox network. It is a subscription-based app that turns your phone into an Internet softphone allowing you to make use of a separate Session Initiation Protocol (SIP) account number on your mobile phone.

Whatsapp is a social messaging mobile application that also allows users to make calls over an Internet connection. The app makes use of the mobile number of the phone the app is installed on.

So, what’s the difference between the two applications when it comes to making voice calls?