Telegram is a messaging app created by former VK creators with a focus on speed and security. It’s superfast, simple and free. It is like SMS, but more powerful.
You can send messages, photos and videos to people who are in your phone contacts (and have Telegram). You can also create groups for up to 20000 people or channels for unlimited subscribers.
Your chats are not encrypted by default, which enables other people to see what you are writing. You can enable a "Secret Chat" to enable end-to-end encryption. More Info »
Telegram's security model has received notable criticism by cryptography experts. They criticized the general security model of permanently storing all contacts, messages and media together with their decryption keys on its servers by default and by not enabling end-to-end encryption for messages by default.
Telegram's client-side code is open-source software, whereas its server-side code is closed-source and proprietary. The service also provides public APIs with which developers can access the same functionality as Telegram's official apps to build their own messaging applications.
Telegram also provides a bot API for programmers to create different kinds of Telegram bots. Bots are simply Telegram accounts operated by software – not people – and they'll often have AI features. They can do anything – teach, play, search, broadcast, remind, connect, integrate with other services, or even pass commands to the Internet of Things.