Telegram is a cloud-based messaging service that collects and retains metadata, including IP addresses. In 2024, Telegram updated its privacy policy to allow sharing of user data with law enforcement upon valid requests, leading to 900 information requests from U.S. authorities affecting 2,253 individuals. The platform has experienced data breaches, including a 2020 leak of data from approximately 42 million Iranian users and a 2019 incident involving the exposure of Hong Kong protestors' identities.
Telegram supports public channels that lack end-to-end encryption, allowing anyone on the platform to view content. It offers secret chats with end-to-end encryption, but these can only be accessed on the user's device. The platform features an automatic message deletion option with a minimum interval of one day and a self-destruct feature for accounts, messages, and contacts after specified inactivity periods.
Telegram's client applications are open-source, but the server-side code is closed-source. The company's cloud servers are encrypted, and encryption keys are stored across various jurisdictions. Telegram operates on a freemium model, providing additional features through a paid subscription while displaying ads in public channels with over 1,000 subscribers. The app is available for download on the Apple App Store and Google Play Store at no cost.