After spending few years at San Jose State University, he got a job at Yahoo and worked there for nine years at first in systems security and then in infrastructure engineering. It was in Yahoo that Koum met Acton. In 2007, the two left Yahoo; and in 2009, they launched WhatsApp.
The simple idea behind the messaging service was to offer people a simple alternative to texting and reach friends and family anywhere in the world on any type of smartphone without having to pay for each message. WhatsApp costs 99 cents for iOS and is free on Android for the first year, and then costs 99 cents. Over the past few years, WhatsApp has achieved phenomenal growth as it now relays billions of messages a day and has 450 million monthly active users. The growth of the messaging service in such a short period of time has even exceeded those of major social networks and messaging services, like Skype, Facebook Messenger, and Twitter.
