I have a doubt regarding the IOS and Android VOIP applications which are popular nowadays. When we install it in our smartphones we receive a free credit of few dollars and the credit gets added when we give invitation to others and they accept it. By repeating the above , our balance will keep on increasing and once we reach certain free credit they will give us a bonus of few dollars(much more than the previous one ) as free. Is it allowed to avail this kind of applications??

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

There is nothing wrong with availing yourself of the rewards offered by IOS and Android VOIP applications in the form of credits to be exchanged for cash or other bonuses in return for downloading and using those applications in permissible manners like inviting people to download them. There is no apparent violation of the Sharee'ah involved.

Allaah Knows best.