Are you on WhatsApp?

[cyber_nomad]

When asking if someone uses WhatsApp what is the correct way?

1. Are you on WhatsApp?
2. Are you contactable on WhatsApp?
3. Do you use WhatsApp?
4. Are you using WhatsApp?

 

[Barque]

Questions 1 and 3 both sound all right to me.

Question 2 doesn't sound natural.

Question 4 means you're asking if the other person's using WhatsApp at that very moment.