Wikipedia
WeChat is a cross-platform instant messaging service developed by Tencent in China, first released in January 2011. It is one of the largest standalone messaging apps by monthly active users.
The app is available on Android, iPhone, BlackBerry, Windows Phone and Symbian phones. Web-based OS X and Windows clients also exist; these however require the user to have the app installed on a supported mobile phone for authentication, and neither message roaming nor 'Moments' are provided. As of May 2016, WeChat has over a billion created accounts, 700 million active users; with more than 70 million outside of China (as of December 2015).
WeChat provides text messaging, hold-to-talk voice messaging, broadcast (one-to-many) messaging, video conferencing, video games, sharing of photographs and videos, and location sharing. It can exchange contacts with people nearby via Bluetooth, as well as providing various features for contacting people at random if desired (if these are open to it), next to integration with social networking services such as those run by Facebook and Tencent QQ. Photographs may also be embellished with filters and captions, and a machine translation service is available.
For work purposes, companies and business communication, a special version of WeChat called Enterprise WeChat (or Qiye Weixin) was launched in April 2016. The app is meant to help employees separate work from private life. Except the usual chat features, the program lets companies and their employees keep track of annual leave days and expenses that need to be reimbursed, employees can ask for time off or even clock in to show they are at work. Security has been upgraded and companies must register before their employees can use the service.