Telegram is a cloud-based mobile and desktop messaging app focused on speed and security. It offers heavily encrypted messages with self-destruct options, multi-device synchronization, no limits on media and chat sizes, and extensive customization. It supports large groups up to 200,000 members and provides an open API and free source code for developers.

platform:android platform:ios platform:windows platform:macos platform:linux platform:web form:mobile-app form:desktop-app form:web-app form:api pricing:free feature:encryption feature:self-destructing-messages feature:multi-device-sync feature:large-groups feature:customization feature:open-source feature:fast-delivery feature:secure target:consumers target:teams target:developers