Messenger app WhatsApp now has 800 million monthly active users, says founder Jan Koum.

The app is up 100 million users since January, when it hit 700 million monthly active users. The app has been expanding rapidly. Just a month ago Google Play showed that WhatsApp had been downloaded on Android over a billion times. With this type of growth the company is poised to hit a billion monthly active users by the end of the year.

Recently WhatsApp expanded its service beyond text messaging to include voice calling.

Facebook acquired the popular messaging app for $22 billion in cash and stock in February 2014. The company has invested not only in WhatsApp, but its own messenger, which recently surpassed 600 million users.