WhatsApp is an instant messaging and voice communication service used by over 2 billion monthly active users, making it the most popular messaging app worldwide. A subsidiary of Meta Platforms (formerly Facebook) and originally a much cheaper alternative to SMS messaging, WhatsApp is especially dominant in international markets such as India and Brazil. In early 2018 WhatsApp Business was introduced to allow businesses to communicate with their customers through WhatsApp. Although WhatsApp is frequently used on mobile, it can also be used on a desktop application or within the browser with WhatsApp Web.