WhatsApp messenger is used for sending instant messages. It is available on all popular mobile operating systems, including Android, iOS, Windows Phone and others. It is also available to use directly from your browser with WhatsApp for Web and on Android Wear, where you can receive notifications directly on your SmartWatch.

Upon installation WhatsApp automatically finds WhatsApp users from your contacts, so you can quickly add them under WhatsApp contacts.

In addition to sending instant messages, users can also send images, videos or voice messages. Group chat allows multiple users to chat at once and another usefull feature is, that users can see if their messages have been read.

Last seen information can be hidden from other users, so they would not know when was the last time you were on WhatsApp.

It uses internet connection for communication (wifi or mobile data plan). That means all the communication is free, in case you don't have to pay for mobile data plan. Even if users with whom you are chatting are in another country, you do not have to pay any additional fees.