Started as an alternative to SMS, WhatsApp has become the most popular cross-platform messaging app. It is available on both Android and iOS. WhatsApp supports sending and receiving a variety of media, including text, photos, videos, documents, and location. It also allows users to make voice call and video calls.
WhatsApp messages and calls are secured with end-to-end encryption, meaning that no third party including WhatsApp can read or listen to them. WhatsApp was founded by Jan Koum and Brian Acton who had previously spent 20 years combined at Yahoo.
WhatsApp joined Facebook in 2014, but continues to operate as a separate app with a laser focus on building a messaging service that works fast and reliably anywhere in the world.
In February 2014, Facebook acquired WhatsApp for approximately $19.3 billion. WhatsApp has grown in multiple countries, including Brazil, India, and large parts of Europe, including the United Kingdom and France.
WhatsApp was officially made available for PCs through a web client, under the name WhatsApp Web, in late January 2015 through an announcement made by Koum on his Facebook page, "Our web client is simply an extension of your phone: the web browser mirrors conversations and messages from your mobile device-this means all of your messages still live on your phone."