Can I WhatsApp between MultiLine users in the app?

No. The other party is required to have an active account on the WhatsApp messaging app.

The WhatsApp messaging connector only allows you to send WhatsApp messages to WhatsApp users from within MultiLine. It is essentially a bridge from MultiLine to a WhatsApp business account. That business account can only send and receive messages from WhatsApp users, not from MultiLine users.

Note however, that we do allow for group chats with WhatsApp users, so multiple MultiLine users can participate in the same chat with a WhatsApp user.