Telegram

Telegram is a cloud-based mobile and desktop messaging app with a focus on security and speed, available on Android, iPhone, Windows, Mac and Linux, plus a web-browser version. It supports encrypted messages that can self-destruct, syncing across multiple devices, group chats that can hold up to 200,000 members, and an open API and source code free for developers to build on. Features include GIFs, custom stickers, welcome messages for new members, a rich text editor for formatting posts, Telegram Communities linking together several groups, channels and bots, and an Instant View feature for reading linked articles within the app.