WhatsApp allows you to only chat with the persons who are in your contact list.We can't Start a chat without saving a number. CHATDIRECT allows you to chat directly without saving any number to your contact list.
There is no need to save the the number to your contact list
Also Using this feature of Chat Direct you can Chat yourself in Whatsapp by Entering your number in this CHATDIRECT App.
Chat Direct also allow you to take no from your call log and open chat on whatsapp directly from chat direct