Telegram is an instant messaging app with a focus on speed and security and a good alternative to WhatsApp. Telegram supports group chats with up to 200 contacts, puts a strong emphasis on security and provides generous multimedia support.
High level of privacy and security
One of Telegram's main features is security and privacy compared to WhatsApp. For example, Telegram has something called "Secret Chats" - an encrypted chat connection that self-destructs messages similar to SnapChat and prevents others intercepting them. In fact, security is one of the things that started attracting users to Telegram in the first place and now that WhatsApp has been bought by Facebook, this looks set to increase. The developers also claim that they do not sell or share user data with third-parties, there is no in-app advertising and yet it's completely free to use.
Send up to 1GB of video
Telegram also features a good level of multimedia support with up to 200 contacts and allows sharing of videos up to 1GB although you may find uploading and downloading quite slow. You can send batches of photos rather than just one at a time and you can store pretty much as many images as you want because Telegram allows unlimited online storage. However, you can't send audio files with Telegram or images in certain formats.
Note that like WhatsApp, Telegram is strictly a messaging app - there's no voice or video calling as yet.
An excellent secure alternative to WhatsApp
If you want an instant messaging client that offers more security than WhatsApp, Telegram is a very interesting alternative.