Hi Bhavesh,
If you want to send invitation for private chat only when user in connected to AppWarp then you can use sendPrivateChat API. You can define message type and associate it along with message in sendPrivateChat. When the chat received at other end, you can check the message type to check if it is a normal message or a invite. If it is a invite then you can process it as invitation request. Once user accepts this request then you callsenPrivateChat API for the acknowledgement to the first user. Once the first user gets invitation acceptance acknowledgement then bith the users can start chatting.
Please let me know if you have any other queries.
Regards,
Rajeev