Send a WhatsApp direct without adding to your contact list
Just fill in the phone number you want to WhatsApp in international form e.g. +1 650 555 7475
Tap and add to homescreen to install this service as a web app
Sometimes you want to sent a WhatsApp message without going to the trouble of adding someone to your contacts. Or you don't want to bloat your contacts list with everyone you ever have sent a WhatsApp message. This service is for you.