WhatsApp Messenger is a proprietary, cross-platform, encrypted instant messaging client for smartphones.[10] It uses the Internet to send text messages, documents, images, video, user location and audio messages[11][12] to other users using standard cellular mobile numbers.

As of February 2016, WhatsApp had a user base of one billion,[13][14] making it the most popular messaging application.[14][15]

WhatsApp Inc., based in Mountain View, California, United States, was acquired by Facebook Inc. on February 19, 2014, for approximately US$19.3 billion.[16][17]