Do you really want to save contact numbers that are actually ad-hoc/temporary in nature? You can use this simple app to send messages to ad-hoc numbers without saving them on phone still getting a nice contact manager for those ad-hoc numbers.
Today's world, so many business professional use whatsapp to reach their customers and expect the customers to reply/interact in WhatsApp. You can use this app to store their number and send instant message in whatsapp.
Please share your valuable feedback/improvements/feature requests to the email id provided. Thanks for checking out!