What's app is an app on ios and android and different softwares. That used for communication. The inventors if the (brian acton and jan koum) the too of them was working in yahoo then. they work in the app after they become independent from they previous job. They published the app in 2010 and become the alternative app for the one how doesn't have blackberry phone because of the easy way to add peoples by there numbers  and chat with them easily. And after the blackberry era ends the app become the most popular app for chatting. After that famous the app have got Facebook have decided to buy the app for 19 billion dollars!. And from since that huge deal what's app is improving day by day.