Owned by Facebook, WhatsApp is easy to understand and completely free to use. All you need is a compatible smartphone and a phone number to use it. Here’s how WhatsApp was founded, its connections to Facebook and how many messages are sent through the service each day.

WhatsApp was founded in 2009 by former Yahoo! employees Brian Acton and Jan Koum. The duo saw the potential of the app industry thanks to the App Store on iOS and began formulating a plan to create an instant messaging app. The app launched exclusively on the App Store for iPhone users in August 2009, before being released for Android in August 2010. As of February 2013, the app had approximately 200 million active users and was valued at $1.5 billion. By the end of 2013, the app had reached 400 million active users.

Originally, it was just a text messaging service. In 2013, voice messaging was added, and in 2015, voice calling. In late 2016, video calling was added, and in 2018, group calling was introduced.

Facebook acquired WhatsApp in February 2014 for $19 billion. It became one of a number of Facebook-owned apps that also included major photo-sharing social networking app Instagram.